Armature and manufacturing method thereof

ABSTRACT

An armature is provided with an armature winding, an armature core and a first and second insulation sheets. The first insulation sheet is arranged to sequentially pass through a field magnet side of a first phase conductor, a portion between the first phase conductor and a second phase conductor, an armature core side of the second phase conductor and a third phase conductor and a portion between the third phase conductor and the first phase conductor. The second insulation sheet is arranged to sequentially pass through a portion opposite to the first phase conductor with respect to the first insulation sheet, a field magnet side of the second conductor, a portion between the second phase conductor and the third phase conductor, a portion between the third phase conductor and the first insulation sheet and a portion between the third phase conductor and the first insulation sheet.

CROSS REFERENCE TO RELATED APPLICATION

This application is the U.S. bypass application of InternationalApplication No. PCT/JP2020/35321 filed on Sep. 17, 2020, whichdesignated the U.S. and claims priority to Japanese Patent ApplicationNo. 2019-170332, filed Sep. 19, 2019, the contents of both of these areincorporated herein by reference.

BACKGROUND Technical Field

The present disclosure relates to an armature and a manufacturing methodthereof.

Description of the Related Art

Conventionally, a rotating electric machine is known. The rotatingelectric machine is provided with a field magnet including a pluralityof magnetic poles having alternating polarities in a circumferentialdirection and an armature disposed facing the field magnet.

SUMMARY

The present disclosure provides an armature having an armature winding,an armature core and a first and second insulation sheets. The firstinsulation sheet is arranged to sequentially pass through a field magnetside of a first phase conductor, a portion between the first phaseconductor and a second phase conductor, an armature core side of thesecond phase conductor and a third phase conductor and a portion betweenthe third phase conductor and the first phase conductor. The secondinsulation sheet is arranged to sequentially pass through a portionopposite to the first phase conductor with respect to the firstinsulation sheet, a field magnet side of the second conductor, a portionbetween the second phase conductor and the third phase conductor, aportion between the third phase conductor and the first insulation sheetand a portion between the third phase conductor and the first insulationsheet.

BRIEF DESCRIPTION OF THE DRAWINGS

The above features and advantages of the present disclosure will beclarified further by the following detailed description with referenceto the accompanying drawings. The drawings are:

FIG. 1 is a vertical cross-sectional perspective view of a rotatingelectric machine.

FIG. 2 is a vertical cross-sectional view of the rotating electricmachine.

FIG. 3 is a sectional view taken along a line III-III of FIG. 2.

FIG. 4 is a cross-sectional view illustrating a part of FIG. 3 in anenlarged manner.

FIG. 5 is an exploded view of the rotating electric machine.

FIG. 6 is an exploded view of an inverter unit.

FIG. 7 is a torque line diagram illustrating a relation betweenampere-turns of a stator winding and torque density.

FIG. 8 is a cross-sectional view of a rotor and a stator.

FIG. 9 is a view illustrating a part of FIG. 8 in an enlarged manner.

FIG. 10 is a cross-sectional view of the stator.

FIG. 11 is a vertical cross-sectional view of the stator.

FIG. 12 is a perspective view of the stator winding.

FIG. 13 is a perspective view illustrating a configuration of aconductor.

FIG. 14 is a schematic diagram illustrating a configuration of wires.

FIG. 15A is a diagram illustrating a form of each conductor in an nthlayer.

FIG. 15B is a diagram illustrating a form of each conductor in an nthlayer.

FIG. 16 is a side view illustrating each conductor of the nth layer andan n+1th layer.

FIG. 17 is a diagram illustrating a relation between an electrical angleand a magnetic flux density of a magnet of an embodiment.

FIG. 18 is a diagram illustrating a relation between an electrical angleand a magnetic flux density of a magnet of a comparative example.

FIG. 19 is an electrical circuit diagram of a control system of therotating electric machine.

FIG. 20 is a functional block diagram illustrating current feedbackcontrol processing by a control device.

FIG. 21 is a functional block diagram illustrating torque feedbackcontrol processing by the control device.

FIG. 22 is a cross-sectional view of a rotor and a stator in a secondembodiment.

FIG. 23 is a view illustrating a part of FIG. 22 in an enlarged manner.

FIG. 24A is a diagram specifically illustrating a flow of magnetic fluxin a magnet unit.

FIG. 24B is a diagram specifically illustrating a flow of magnetic fluxin a magnet unit.

FIG. 25 is a cross-sectional view of a stator in a first modification.

FIG. 26 is a cross-sectional view of the stator in the firstmodification.

FIG. 27 is a cross-sectional view of a stator in a second modification.

FIG. 28 is a cross-sectional view of a stator in a third modification.

FIG. 29 is a cross-sectional view of a stator in a fourth modification.

FIG. 30 is a cross-sectional view of a rotor and a stator in a seventhmodification.

FIG. 31 is a functional block diagram illustrating a part of theprocessing of an operation signal generation unit in a eighthmodification.

FIG. 32 is a flowchart illustrating a procedure of carrier frequencychanging processing.

FIG. 33A is a diagram illustrating a connection form of each conductorconstituting a conductor group in a ninth modification.

FIG. 33B is a diagram illustrating a connection form of each conductorconstituting a conductor group in a ninth modification.

FIG. 33C is a diagram illustrating a connection form of each conductorconstituting a conductor group in a ninth modification.

FIG. 34 is a diagram illustrating a configuration in which four pairs ofconductors are laminated in the ninth modification.

FIG. 35 is a cross-sectional view of an inner rotor type rotor and astator in tenth modification.

FIG. 36 is a view illustrating a part of FIG. 35 in an enlarged manner.

FIG. 37 is a vertical cross-sectional view of an inner rotor typerotating electric machine.

FIG. 38 is a vertical cross-sectional view illustrating a schematicconfiguration of the inner rotor type rotating electric machine.

FIG. 39 is a diagram illustrating a configuration of a rotating electricmachine having an inner rotor structure in a eleventh modification.

FIG. 40 is a diagram illustrating a configuration of a rotating electricmachine having an inner rotor structure in the eleventh modification.

FIG. 41 is a diagram illustrating a configuration of a rotating electricmachine having an inner rotor structure in a twelfth modification.

FIG. 42 is a cross-sectional view illustrating a configuration of aconductor in a fourteenth modification.

FIG. 43 is a diagram illustrating a relation between a reluctancetorque, a magnet torque, and DM.

FIG. 44 is a diagram illustrating teeth.

FIG. 45 is a perspective view illustrating a wheel having an in-wheelmotor structure and its peripheral structure.

FIG. 46 is a vertical cross-sectional view of the wheel and itsperipheral structure.

FIG. 47 is an exploded perspective view of the wheel.

FIG. 48 is a side view of a rotating electric machine as viewed from theprotruding side of a rotating shaft.

FIG. 49 is a cross-sectional view taken along a line 49-49 of FIG. 48.

FIG. 50 is a cross-sectional view taken along a line 50-50 of FIG. 49.

FIG. 51 is an exploded cross-sectional view of the rotating electricmachine.

FIG. 52 is a partial cross-sectional view of the rotor.

FIG. 53 is a perspective view of a stator winding and a star core.

FIG. 54A is a front view illustrating the stator winding developed in aplane.

FIG. 54B is a front view illustrating the stator winding developed in aplane.

FIG. 55 is a diagram illustrating a skew of the conductor.

FIG. 56 is an exploded cross-sectional view of the inverter unit.

FIG. 57 is an exploded cross-sectional view of the inverter unit.

FIG. 58 is a diagram illustrating a state of arrangement of eachelectric module in an inverter housing.

FIG. 59 is a circuit diagram illustrating an electrical configuration ofa power converter.

FIG. 60 is a diagram illustrating an example of a cooling structure of aswitch module.

FIG. 61A is a diagram illustrating an example of the cooling structureof the switch module.

FIG. 61B is a diagram illustrating an example of the cooling structureof the switch module.

FIG. 62A is a diagram illustrating an example of the cooling structureof the switch module.

FIG. 62B is a diagram illustrating an example of the cooling structureof the switch module.

FIG. 62C is a diagram illustrating an example of the cooling structureof the switch module.

FIG. 63A is a diagram illustrating an example of the cooling structureof the switch module.

FIG. 63B is a diagram illustrating an example of the cooling structureof the switch module.

FIG. 64 is a diagram illustrating an example of the cooling structure ofthe switch module.

FIG. 65 is a diagram illustrating an arrangement order of each electricmodule with respect to a cooling water passage.

FIG. 66 is a cross-sectional view taken along a line 66-66 of FIG. 49.

FIG. 67 is a cross-sectional view taken along a line 67-67 of FIG. 49.

FIG. 68 is a perspective view illustrating a busbar module alone.

FIG. 69 is a diagram illustrating an electrical connection state betweeneach electric module and the busbar module.

FIG. 70 is a diagram illustrating an electrical connection state betweeneach electric module and the busbar module.

FIG. 71 is a diagram illustrating an electrical connection state betweeneach electric module and the busbar module.

FIG. 72A is a configuration diagram for explaining a first modificationin an in-wheel motor.

FIG. 72B is a configuration diagram for explaining a first modificationin an in-wheel motor.

FIG. 72C is a configuration diagram for explaining a first modificationin an in-wheel motor.

FIG. 72D is a configuration diagram for explaining a first modificationin an in-wheel motor.

FIG. 73A is a configuration diagram for explaining a second modificationin the in-wheel motor.

FIG. 73B is a configuration diagram for explaining a second modificationin the in-wheel motor.

FIG. 73C is a configuration diagram for explaining a second modificationin the in-wheel motor.

FIG. 74A is a configuration diagram for explaining a third modificationin the in-wheel motor.

FIG. 74B is a configuration diagram for explaining a third modificationin the in-wheel motor.

FIG. 75 is a configuration diagram for explaining a fourth modificationin the in-wheel motor.

FIG. 76 is a process control chart showing a manufacturing process of astator according a fifteenth modification.

FIG. 77A is a diagram showing a manufacturing mode of a first assemblyand a second assembly.

FIG. 77B is a diagram showing a manufacturing mode of a first assemblyand a second assembly.

FIG. 78A is a diagram showing a lamination mode of the first assembly,the second assembly and a third insulation sheet.

FIG. 78B is a diagram showing a lamination mode of the first assembly,the second assembly and a third insulation sheet.

FIG. 79 is a cross sectional view of a stator.

FIG. 80 is a cross sectional view of a stator according to a comparativeexample.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

As a conventional art, for example, Japanese Patent ApplicationLaid-Open Publication No. 2011-24379 discloses a rotating electricmachine provided with a field magnet including a plurality of magneticpoles having alternating polarities in a circumferential direction andan armature disposed facing the field magnet. The armature includes athree-phase armature winding and an armature core disposed in anopposite side of the field magnet via the armature winding.

The armature winding includes conductors arranged in the circumferentialdirection at predetermined intervals in the order of the first phase,the second phase and the third phase (e.g. U phase, V phase, W phase).An interphase insulation is required between respective conductors.

In this respect, a resin molding in which synthetic resin is filledbetween respective conductors may be utilized for performing theinterphase insulation. In this case, if air bubble is present which maybridge between adjacent phases in the synthetic resin between conductorsof adjacently positioned phases in the circumferential direction, asurface discharge possibly occurs between adjacent conductors via theair bubble.

In order to suppress such a surface discharge, a method of performing aninterphase insulation using an insulation sheet such as insulationpapers and the like may be utilized. According to this method,conductors of respective phases are wound around individual insulationsheet. In this case, since insulation sheet for two layers are presentbetween conductors adjacently positioned in the circumferentialdirection, the insulation sheet occupies large area in the space betweenadjacent conductors. Hence, the technique of performing the interphaseinsulation using the insulation sheet still needs to be improved.

Hereinafter, a plurality of embodiments will be described with referenceto the drawings. In the plurality of embodiments, functionally and/orstructurally corresponding parts and/or associated parts may bedesignated with the same reference sign or reference signs that aredifferent in the hundreds or higher position. For corresponding and/orassociated parts, the description of other embodiments can be referredto.

The rotating electric machine in this embodiment is used, for example,as a vehicle power source. However, the rotating electric machine can bewidely used for industrial use, vehicle use, home appliance use, OAequipment use, game machine use, and the like. Note that, in each of thefollowing embodiments, parts that are the same or equivalent to eachother are designated by the same reference signs in the drawings, andthe description thereof will be incorporated for the parts having thesame reference signs.

First Embodiment

A rotating electric machine 10 according to the present embodiment is asynchronous multi-phase AC motor and has an outer rotor structure (outerrotating structure). The outline of the rotating electric machine 10 isillustrated in FIGS. 1 to 5. FIG. 1 is a vertical cross-sectionalperspective view of the rotating electric machine 10, FIG. 2 is avertical cross-sectional view of the rotating electric machine 10 in adirection along a rotating shaft 11, FIG. 3 is a cross-sectional view ofthe rotating electric machine 10 in a direction orthogonal to therotating shaft 11 (cross-sectional view taken along a line III-III ofFIG. 2), FIG. 4 is a cross-sectional view illustrating a part of FIG. 3in an enlarged manner, and FIG. 5 is an exploded view of the rotatingelectric machine 10. Note that, in FIG. 3, for convenience ofillustration, hatching indicating a cut surface is omitted except for arotating shaft 11. In the following description, the direction in whichthe rotating shaft 11 extends is the axial direction, the directionextending radially from the center of the rotating shaft 11 is theradial direction, and the direction extending circumferentially aroundthe rotating shaft 11 is the circumferential direction.

The rotating electric machine 10 includes, substantially, a bearing unit20, a housing 30, a rotor 40, a stator 50, and an inverter unit 60. Eachof these members is arranged coaxially with the rotating shaft 11 and isassembled in the axial direction in a predetermined order to form therotating electric machine 10. The rotating electric machine 10 of thepresent embodiment has a configuration having a rotor 40 as a “fieldmagnet” and a stator 50 as an “armature”, and is embodied as arevolving-field type rotating electric machine.

The bearing unit 20 includes two bearings 21 and 22 arranged apart fromeach other in the axial direction, and a holding member 23 that holdsthe bearings 21 and 22. The bearings 21 and 22 are, for example, radialball bearings, each of which has an outer ring 25, an inner ring 26, anda plurality of balls 27 arranged between the outer ring 25 and the innerring 26. The holding member 23 has a cylindrical shape, and the bearings21 and 22 are assembled radially thereinside. In addition, the rotatingshaft 11 and the rotor 40 are rotatably supported radially inside thebearings 21 and 22. The bearings 21 and 22 constitute a pair of bearingsthat rotatably support the rotating shaft 11.

In the respective bearings 21 and 22, balls 27 are held by retainers(not illustrated), and the pitch between the balls is maintained in thatstate. The bearings 21 and 22 has sealing members at the upper and lowerportions in the axial direction of the retainer, and the inside of thesealing members is filled with nonconductive grease (for example,nonconductive urea grease). Further, the position of the inner ring 26is mechanically held by a spacer, and a constant pressure preload thatrises in the up-down direction from the inside is applied.

A housing 30 has a cylindrical peripheral wall 31. The peripheral wall31 has a first end and a second end facing each other in the axialdirection thereof. The peripheral wall 31 has an end face 32 at thefirst end and an opening 33 at the second end. The opening 33 is openthroughout the second end. A circular hole 34 is formed in the center ofthe end face 32, and a bearing unit 20 is fixed by a fixture such as ascrew or a rivet in a state of being inserted through the hole 34.Further, a hollow cylindrical rotor 40 and a hollow cylindrical stator50 are housed in the housing 30, that is, in the internal spacepartitioned by the peripheral wall 31 and the end face 32. In thepresent embodiment, the rotating electric machine 10 is an outer rotortype, and in the housing 30, the stator 50 is arranged radially insidethe cylindrical rotor 40. The rotor 40 is cantilevered and supported bythe rotating shaft 11 on the side of the end face 32 in the axialdirection.

The rotor 40 has a magnet holder 41 formed in a hollow tubular shape andan annular magnet unit 42 provided radially inside the magnet holder 41.The magnet holder 41 has a substantially cup shape and has a function asa magnet holding member. The magnet holder 41 has a cylindrical section43 having a cylindrical shape, a fixing section (attachment) 44 having acylindrical shape and a diameter smaller than that of the cylindricalsection 43, and an intermediate section 45 serving as a part connectingthe cylindrical section 43 and the fixing section 44. The magnet unit 42is attached to the inner peripheral surface of the cylindrical section43.

Moreover, the magnet holder 41 is made of a steel plate cold commercial(SPCC) having sufficient mechanical strength, forging steel, carbonfiber reinforced plastic (CFRP), or the like.

The rotating shaft 11 is inserted through a through hole 44 a of thefixing section 44. The fixing section 44 is fixed to the rotating shaft11 arranged in the through hole 44 a. That is, the magnet holder 41 isfixed to the rotating shaft 11 by the fixing section 44. Moreover, thefixing section 44 is preferably fixed to the rotating shaft 1 by splinecoupling, key coupling, welding, caulking, or the like using aprotrusion and a recess. As a result, the rotor 40 rotates integrallywith the rotating shaft 11.

Further, bearings 21 and 22 of the bearing unit 20 are assembledradially inside the fixing section 44. Since the bearing unit 20 isfixed to the end face 32 of the housing 30 as described above, therotating shaft 11 and the rotor 40 are rotatably supported by thehousing 30. As a result, the rotor 40 is rotatable in the housing 30.

The rotor 40 is provided with the fixing section 44 only on one of thetwo ends facing in the axial direction, whereby the rotor 40 iscantilevered and supported by the rotating shaft 11. Here, the fixingsection 44 of the rotor 40 is rotatably supported by the bearings 21 and22 of the bearing unit 20 at two positions different in the axialdirection. In other words, the rotor 40 is rotatably supported by thetwo bearings 21 and 22 separated in the axial direction at one of thetwo ends of the magnet holder 41 facing in the axial direction.Therefore, even if the rotor 40 is cantilevered and supported by therotating shaft 11, stable rotation of the rotor 40 can be achieved. Inthis case, the rotor 40 is supported by the bearings 21 and 22 at aposition displaced to one side with respect to the axial center positionof the rotor 40.

Further, in the bearing unit 20, the bearing 22 near the center of therotor 40 (lower side in the figure) and the bearing 21 on the oppositeside (upper side in the figure) have different gap dimensions betweenthe outer ring 25 and the inner ring 26, and the ball 27, and forexample, the bearing 22 near the center of the rotor 40 has a larger gapdimension than that of the bearing 21 on the opposite side. In thiscase, even if shaking of the rotor 40 or vibration due to imbalancecaused by component tolerance acts on the bearing unit 20 on the sidecloser to the center of the rotor 40, the influence of the shake orvibration is well absorbed. Specifically, by increasing the allowancedimension (gap dimension) by preloading the bearing 22 near the centerof the rotor 40 (lower side of the figure), the vibration generated inthe cantilever structure is absorbed by the allowance portion. Thepreload may be either a fixed position preload or a constant pressurepreload. In the case of fixed position preload, both the outer rings 25of the bearing 21 and the bearing 22 are joined to the holding member 23by a method such as press fitting or adhesion. Further, both the innerrings 26 of the bearing 21 and the bearing 22 are joined to the rotatingshaft 11 by a method such as press fitting or adhesion. Here, thepreload can be generated by arranging the outer ring 25 of the bearing21 at a different position in the axial direction with respect to theinner ring 26 of the bearing 21. The preload can also be generated byarranging the outer ring 25 of the bearing 22 at a different position inthe axial direction with respect to the inner ring 26 of the bearing 22.

Further, in a case where a constant pressure preload is adopted, apreload spring, for example, a waved washer 24 or the like is arrangedin the same region sandwiched between the bearing 22 and the bearing 21in such a manner that preload is generated from the region sandwichedbetween the bearing 22 and the bearing 21 toward the outer ring 25 ofthe bearing 22 in the axial direction. Also in this case, both the innerrings 26 of the bearing 21 and the bearing 22 are joined to the rotatingshaft 11 by a method such as press fitting or adhesion. The bearing 21or the outer ring 25 of the bearing 22 is arranged with respect to theholding member 23 via a predetermined clearance. With such aconfiguration, the spring force of the preload spring acts on the outerring 25 of the bearing 22 in the direction away from the bearing 21.Then, when this force is transmitted through the rotating shaft 11, aforce that presses the inner ring 26 of the bearing 21 in the directionof the bearing 22 acts. As a result, the positions of the outer ring 25and the inner ring 26 in the axial direction of both the bearings 21 and22 are displaced, and the two bearings can be preloaded in the samemanner as the aforementioned fixed position preload.

Moreover, when generating the constant pressure preload, it is notalways necessary to apply the spring force to the outer ring 25 of thebearing 22 as illustrated in FIG. 2. For example, the spring force maybe applied to the outer ring 25 of the bearing 21. Further, the innerring 26 of either of the bearings 21 and 22 may be arranged with respectto the rotating shaft 11 via a predetermined clearance, and the outerring 25 of the bearings 21 and 22 may be joined to the holding member 23by press fitting or adhesion, thereby preloading the two bearings.

Furthermore, in a case where a force is applied in such a manner thatthe inner ring 26 of the bearing 21 is separated from the bearing 22, itis better to apply a force in such a manner that the inner ring 26 ofthe bearing 22 is also separated from the bearing 21. On the contrary,in a case where a force is applied in such a manner that the inner ring26 of the bearing 21 approaches the bearing 22, it is better to apply aforce in such a manner that the inner ring 26 of the bearing 22 alsoapproaches the bearing 21.

Moreover, in a case where the rotating electric machine 10 is applied toa vehicle for the purpose of a vehicle power source or the like, thereis a possibility that vibration having a component in the preloadgeneration direction is applied to a mechanism that generates thepreload, and the direction of gravity applied to an object to which thepreload is applied may fluctuate. Therefore, in the case where therotating electric machine 10 is applied to a vehicle, it is desirable toadopt a fixed position preload.

Further, the intermediate section 45 has an annular inner shouldersection 49 a and an annular outer shoulder section 49 b. The outershoulder section 49 b is located outside the inner shoulder section 49 ain the radial direction of the intermediate section 45. The innershoulder section 49 a and the outer shoulder section 49 b are separatedfrom each other in the axial direction of the intermediate section 45.As a result, the cylindrical section 43 and the fixing section 44partially overlap in the radial direction of the intermediate section45. That is, the cylindrical section 43 protrudes outward in the axialdirection from the base end portion (back side end portion on the lowerside in the figure) of the fixing section 44. In this configuration, therotor 40 can be supported with respect to the rotating shaft 11 at aposition near the center of gravity of the rotor 40, as compared with acase where the intermediate section 45 is provided in a flat plate shapewithout a step, and the operational stability of the rotor 40 can beachieved.

According to the configuration of the intermediate section 45 describedabove, in the rotor 40, a bearing housing recess 46 that houses a partof the bearing unit 20 is formed in an annular shape at a position thatsurrounds the fixing section 44 in the radial direction and is inward ofthe intermediate section 45, and a coil housing recess 47 that housesthe coil end 54 of the stator winding 51 of the stator 50 which will bedescribed below is formed at a position that surrounds the bearinghousing recess 46 in the radial direction and is outward of theintermediate section 45. In addition, these respective housing recesses46 and 47 are arranged so as to be adjacent to each other inside andoutside in the radial direction. That is, a part of the bearing unit 20and the coil end 54 of the stator winding 51 are arranged so as tooverlap inside and outside in the radial direction. This makes itpossible to shorten the axial length dimension in the rotating electricmachine 10.

The intermediate section 45 is provided so as to project radiallyoutward from the rotating shaft 11 side. In addition, the intermediatesection 45 is provided with a contact avoiding section that extends inthe axial direction and avoids contact of the stator winding 51 of thestator 50 with respect to the coil end 54. The intermediate section 45corresponds to a projecting section.

By bending the coil end 54 inward or outward in the radial direction,the axial dimension of the coil end 54 can be reduced, and the axiallength of the stator 50 can be shortened. The bending direction of thecoil end 54 may be in consideration of assembly with the rotor 40.Assuming that the stator 50 is assembled radially inside the rotor 40,the coil end 54 may be preferably bent radially inside on the insertiontip side with respect to the rotor 40. The bending direction of the coilend on the side opposite to the coil end 54 may be arbitrary, but ashape in which the coil end is bent outward with a sufficient space ispreferable in manufacturing.

Further, the magnet unit 42 as a magnet section is composed of aplurality of permanent magnets that are arranged on the radial inside ofthe cylindrical section 43 in such a manner that the polaritiesalternate along the circumferential direction. As a result, the magnetunit 42 has a plurality of magnetic poles in the circumferentialdirection. However, the details of the magnet unit 42 will be describedbelow.

The stator 50 is provided radially inside the rotor 40. The stator 50has a stator winding 51 formed by winding in a substantially tubularshape (annular shape) and a stator core 52 as a base member arrangedradially inside the stator winding 51. The stator winding 51 is arrangedso as to face the annular magnet unit 42 with a predetermined air gaptherebetween. The stator winding 51 is composed of a plurality of phasewindings. Each of these phase windings is configured by connecting aplurality of conductors arranged in the circumferential direction toeach other at a predetermined pitch. In the present embodiment, aU-phase, V-phase, and W-phase three-phase winding and an X-phase.Y-phase, and Z-phase three-phase winding are used. Two of thesethree-phase windings are used, and the stator winding 51 is therebyconfigured as a six-phase winding.

The stator core 52 is formed in an annular shape by laminated steelsheets in which electromagnetic steel sheets which are soft magneticmaterials are laminated, and is assembled radially inside the statorwinding 51. The electromagnetic steel sheet is, for example, a siliconsteel sheet in which approximately several % (for example, 3%) ofsilicon is added to iron. The stator winding 51 corresponds to anarmature winding, and the stator core 52 corresponds to an armaturecore.

The stator winding 51 is a portion that overlaps the stator core 52 inthe radial direction, and has a coil side section 53 that is radiallyoutside the stator core 52, and coil ends 54 and 55 that respectivelyproject to one end side and to the other end side of the stator core 52in the axial direction. The coil side section 53 faces the stator core52 and the magnet unit 42 of the rotor 40 in the radial direction,respectively. In a state where the stator 50 is arranged inside therotor 40, the coil end 54 on the side of the bearing unit 20 (upper sidein the figure) of the coil ends 54 and 55 on both sides in the axialdirection is housed in the in the coil housing recess 47 formed by themagnet holder 41 of the rotor 40. Note that, the details of the stator50 will be described below.

The inverter unit 60 has a unit base 61 fixed to the housing 30 byfasteners such as bolts, and a plurality of electric components 62assembled to the unit base 61. The unit base 61 is made of, for example,carbon fiber reinforced plastic (CFRP). The unit base 61 has an endplate 63 fixed to the edge of the opening 33 of the housing 30, and acasing 64 integrally provided with the end plate 63 and extending in theaxial direction. The end plate 63 has a circular opening 65 at thecenter thereof, and the casing 64 is formed so as to stand up from theperipheral edge portion of the opening 65.

The stator 50 is assembled on the outer peripheral surface of the casing64. That is, the outer diameter dimension of the casing 64 is the sameas the inner diameter dimension of the stator core 52, or slightlysmaller than the inner diameter dimension of the stator core 52. Byassembling the stator core 52 to the outside of the casing 64, thestator 50 and the unit base 61 are integrated. Further, since the unitbase 61 is fixed to the housing 30, the stator 50 is integrated with thehousing 30 in a state where the stator core 52 is assembled to thecasing 64.

Moreover, the stator core 52 is preferably assembled to the unit base 61by adhesion, shrink fitting, press fitting, or the like. As a result,the displacement of the stator core 52 in the circumferential directionor the axial direction with respect to the unit base 61 side issuppressed.

Further, the radial inside of the casing 64 is a housing space forhousing the electric component 62, and the electric component 62 isarranged in the housing space so as to surround the rotating shaft 11.The casing 64 has a role as a housing space forming section. Theelectric component 62 includes a semiconductor module 66 constituting aninverter circuit, a control board 67, and a capacitor module 68.

Moreover, the unit base 61 is provided radially inside the stator 50 andcorresponds to a stator holder (armature holder) that holds the stator50. The housing 30 and the unit base 61 constitute the motor housing ofthe rotating electric machine 10. In this motor housing, the holdingmember 23 is fixed to the housing 30 on one side in the axial directionwith the rotor 40 therebetween, and the housing 30 and the unit base 61are coupled to each other on the other side. For example, in a motorvehicle or the like which is an electric car, the rotating electricmachine 10 is mounted to the motor car or the like by attaching a motorhousing to the side of the motor car or the like.

Here, the configuration of the inverter unit 60 will be furtherdescribed with reference to FIG. 6 which is an exploded view of theinverter unit 60, in addition to FIGS. 1 to 5 described above.

In the unit base 61, the casing 64 has a tubular section 71 and an endface 72 provided on one (end on the bearing unit 20 side) of both endsfacing each other in the axial direction thereof. Of the both ends ofthe tubular section 71 in the axial direction, the side opposite to theend face 72 is completely opened through the opening 65 of the end plate63. A circular hole 73 is formed in the center of the end face 72, andthe rotating shaft 11 can be inserted into the hole 73. The hole 73 isprovided with a sealing material 171 that seals the space between thehole 73 and the outer peripheral surface of the rotating shaft 11. Thesealing material 171 is preferably, for example, a sliding seal made ofa resin material.

The tubular section 71 of the casing 64 is a partition section thatpartitions between the rotor 40 and the stator 50 arranged radiallyoutside and the electric component 62 arranged radially inside. Therotor 40, the stator 50, and the electric component 62 are arranged sideby side radially inside and outside with the tubular section 71therebetween.

Further, the electric component 62 is an electric component constitutingan inverter circuit, and has a power running function of passing acurrent through each phase winding of the stator winding 51 in apredetermined order to rotate the rotor 40 and a power generationfunction of inputting a three-phase AC current flowing through thestator winding 51 with the rotation of the rotating shaft 11 andoutputting same to the outside as generated power. Moreover, theelectric component 62 may have only one of the power running functionand the power generation function. The power generation function is, forexample, a regenerative function that outputs regenerative power to theoutside when the rotating electric machine 10 is used as a power sourcefor a vehicle.

As a specific configuration of the electric component 62, as illustratedin FIG. 4, a hollow cylindrical capacitor module 68 is provided aroundthe rotating shaft 11, and a plurality of semiconductor modules 66 arearranged side by side in the circumferential direction on the outerperipheral surface of the capacitor module 68. The capacitor module 68includes a plurality of smoothing capacitors 68 a connected in parallelto each other. Specifically, the capacitor 68 a is a laminated filmcapacitor in which a plurality of film capacitors are laminated, and hasa trapezoidal cross section. The capacitor module 68 is configured byarranging twelve capacitors 68 a side by side in an annular shape.

Moreover, in the manufacturing process of the capacitor 68 a, forexample, a long film having a predetermined width in which a pluralityof films are laminated is used, the film width direction is thetrapezoid height direction, and the long film is cut into an isoscelestrapezoid shape in such a manner that the upper bottom and the lowerbottom of the trapezoid alternate, thereby making a capacitor element.Then, the capacitor 68 a is manufactured by attaching an electrode orthe like to the capacitor element.

The semiconductor module 66 has a semiconductor switching element suchas a MOSFET or an IGBT, and is formed in a substantially plate shape. Inthe present embodiment, since the rotating electric machine 10 includestwo sets of three-phase windings and an inverter circuit is provided foreach of the three-phase windings, a semiconductor module group 66Aformed by arranging a total of 12 semiconductor modules 66 in an annularshape is provided in the electric component 62.

The semiconductor module 66 is arranged in a state of being sandwichedbetween the tubular section 71 of the casing 64 and the capacitor module68. The outer peripheral surface of the semiconductor module group 66Ais in contact with the inner peripheral surface of the tubular section71, and the inner peripheral surface of the semiconductor module group66A is in contact with the outer peripheral surface of the capacitormodule 68. In this case, the heat generated in the semiconductor module66 is transferred to the end plate 63 via the casing 64 and releasedfrom the end plate 63.

The semiconductor module group 66A preferably has a spacer 69 betweenthe semiconductor module 66 and the tubular section 71 on the outerperipheral surface side, that is, in the radial direction. In this case,in the capacitor module 68, the cross-sectional shape of the crosssection orthogonal to the axial direction is a regular dodecagon,whereas the cross-sectional shape of the inner peripheral surface of thetubular section 71 is circular. Thus, the inner peripheral surface ofthe spacer 69 is a flat surface and the outer peripheral surface of thespacer 69 is a curved surface. The spacer 69 may be integrally providedso as to be connected in an annular shape on the radial outside of thesemiconductor module group 66A. The spacer 69 is a good thermalconductor, and is preferably, for example, a metal such as aluminum, aheat radiating gel sheet, or the like. Moreover, it is also possible tomake the cross-sectional shape of the inner peripheral surface of thetubular section 71 the same dodecagon as that of the capacitor module68. In this case, it is preferable that both the inner peripheralsurface and the outer peripheral surface of the spacer 69 are flatsurfaces.

Further, in the present embodiment, a cooling water passage 74 forflowing cooling water is formed in the tubular section 71 of the casing64, and the heat generated in the semiconductor module 66 is alsoreleased to the cooling water flowing through the cooling water passage74. That is, the casing 64 is provided with a water-cooling mechanism.As illustrated in FIGS. 3 and 4, the cooling water passage 74 is formedin an annular shape so as to surround the electric component 62 (thesemiconductor module 66 and the capacitor module 68). The semiconductormodule 66 is arranged along the inner peripheral surface of the tubularsection 71, and the cooling water passage 74 is provided at a positionoverlapping the semiconductor module 66 inside and outside in the radialdirection.

Since the stator 50 is arranged on the outside of the tubular section 71and the electric component 62 is arranged on the inside of the tubularsection 71, the heat of the stator 50 is transferred to the tubularsection 71 from the outside, and the heat of the electric component 62(for example, the heat of the semiconductor module 66) is transferredfrom the inside. In this case, the stator 50 and the semiconductormodule 66 can be cooled at the same time, and the heat of theheat-generating member in the rotating electric machine 10 can beefficiently released.

Furthermore, at least a part of the semiconductor module 66 constitutinga part or the whole of the inverter circuit that operates the rotatingelectric machine by energizing the stator winding 51 is arranged in aregion surrounded by the stator core 52 arranged radially outside thetubular section 71 of the casing 64. Preferably, the entire onesemiconductor module 66 is arranged in a region surrounded by the statorcore 52. Furthermore, preferably, the whole of all the semiconductormodules 66 is arranged in a region surrounded by the stator core 52.

Further, at least a part of the semiconductor module 66 is arranged in aregion surrounded by the cooling water passage 74. Preferably, the wholeof all the semiconductor modules 66 is arranged in a region surroundedby a yoke 141.

Further, the electric component 62 includes an insulating sheet 75provided on one end face of the capacitor module 68 and a wiring module76 provided on the other end face in the axial direction. In this case,the capacitor module 68 has two end faces facing each other in the axialdirection, that is, a first end face and a second end face. The firstend face of the capacitor module 68 near the bearing unit 20 faces theend face 72 of the casing 64, and is superimposed on the end face 72with the insulating sheet 75 sandwiched therebetween. Further, a wiringmodule 76 is assembled on the second end face of the capacitor module 68near the opening 65.

The wiring module 76 has a main body section 76 a made of a syntheticresin material and having a circular plate shape and a plurality of busbars 76 b, 76 c embedded therein, and the bus bars 76 b, 76 c form anelectrical connection with the semiconductor module 66 and the capacitormodule 68. Specifically, the semiconductor module 66 has a connectingpin 66 a extending from its axial end face, and the connecting pin 66 ais connected to the busbar 76 b on the radial outside of the main bodysection 76 a. Further, a busbar 76 c extends to the side opposite to thecapacitor module 68 on the radial outside of the main body section 76 a,and is connected to a wiring member 79 at the tip end portion thereof(see FIG. 2).

As described above, according to the configuration in which theinsulating sheet 75 is provided on the first end face of the capacitormodule 68 facing the axial direction and the wiring module 76 isprovided on the second end face of the capacitor module 68, as a heatdissipation path of the capacitor module 68, a path from the first endface and the second end face of the capacitor module 68 to the end face72 and the tubular section 71 is formed. In other words, a path from thefirst end face to the end face 72 and a path from the second end face tothe tubular section 71 are formed. As a result, heat can be dissipatedfrom the end face portion of the capacitor module 68 other than theouter peripheral surface on which the semiconductor module 66 isprovided. That is, not only heat dissipation in the radial direction butalso heat dissipation in the axial direction is possible.

Further, since the capacitor module 68 has a hollow cylindrical shapeand the rotating shaft 11 is arranged on the inner peripheral portionthereof with a predetermined gap interposed therebetween, the heat ofthe capacitor module 68 can be released from the hollow portion as well.In this case, the rotation of the rotating shaft 11 causes an air flowto enhance the cooling effect.

A disk-shaped control board 67 is attached to the wiring module 76. Thecontrol board 67 has a printed circuit board (PCB) on which apredetermined wiring pattern is formed, and a control device 77corresponding to a control unit composed of various ICs and amicrocomputer is mounted on the board. The control board 67 is fixed tothe wiring module 76 by a fixture such as a screw. The control board 67has, in the central portion thereof, an insertion hole 67 a in which therotation shaft 11 is inserted.

Moreover, the wiring module 76 has a first surface and a second surfacethat face each other in the axial direction, that is, face each other inthe thickness direction thereof. The first surface faces the capacitormodule 68. The wiring module 76 is provided with the control board 67 onthe second surface thereof. The busbar 76 c of the wiring module 76extends from one side of both sides of the control board 67 to the otherside. In such a configuration, the control board 67 is preferablyprovided with a notch to avoid interference with the busbar 76 c. Forexample, a part of the outer edge portion of the control board 67 havinga circular shape is preferably notched.

As described above, according to the configuration in which the electriccomponent 62 is housed in the space surrounded by the casing 64, and thehousing 30, the rotor 40 and the stator 50 are provided in layers on theoutside thereof, the electromagnetic noise generated in the invertercircuit is suitably shielded. In other words, in the inverter circuit,switching control is performed in each semiconductor module 66 byutilizing PWM control using a predetermined carrier frequency, and it isconceivable that electromagnetic noise is generated by the switchingcontrol. However, the noise can be suitably shielded by the housing 30,the rotor 40, the stator 50, and the like on the radially outside theelectric component 62.

Furthermore, at least a part of the semiconductor module 66 is arrangedin the region surrounded by the stator core 52 arranged radially outsidethe tubular section 71 of the casing 64. Thus, compared to aconfiguration in which the semiconductor module 66 and the statorwinding 51 are arranged without the stator core 52, even if magneticflux is generated from the semiconductor module 66, the stator winding51 is less likely to be affected. Further, even if the magnetic flux isgenerated from the stator winding 51, it is unlikely to affect thesemiconductor module 66. Moreover, it is more effective if the entiresemiconductor module 66 is arranged in a region surrounded by the statorcore 52 arranged radially outside the tubular section 71 of the casing64. Further, in a case where at least a pan of the semiconductor module66 is surrounded by the cooling water passage 74, it is possible toobtain the effect that the heat generated from the stator winding 51 andthe magnet unit 42 is suppressed from reaching the semiconductor module66.

In the tubular section 71, a through hole 78 is formed in the vicinityof the end plate 63, through which the wiring member 79 (see FIG. 2)that electrically connects the outer stator 50 and the inner electriccomponent 62 is inserted. As illustrated in FIG. 2, the wiring member 79is connected to the end of the stator winding 51 and the busbar 76 c ofthe wiring module 76 by crimping, welding, or the like, respectively.The wiring member 79 is, for example, a busbar, and it is desirable thatthe joint surface thereof be flattened. The through holes 78 arepreferably provided at one place or a plurality of places, and in thepresent embodiment, the through holes 78 are provided at two places. Inthe configuration in which the through holes 78 are provided at twoplaces, the winding terminals extending from the two sets of three-phasewindings can be easily connected by the wiring members 79 respectively,which is suitable for performing multi-phase connection.

As described above, as illustrated in FIG. 4, the rotor 40 and thestator 50 are provided in the housing 30 in this order from the outsidein the radial direction, and an inverter unit 60 is provided radiallyinside the stator 50. Here, when the radius of the inner peripheralsurface of the housing 30 is d, the rotor 40 and the stator 50 arearranged radially outside the distance of d*0.705 from the center ofrotation of the rotor 40. In this case, when the region of the rotor 40and the stator 50, that is radially inside from the inner peripheralsurface of the stator 50 that is inside in the radial direction (thatis, the inner peripheral surface of the stator core 52) is a firstregion X1, and the region between the inner peripheral surface of thestator 50 and the housing 30 is a second region X2, the cross-sectionalarea of the first region X1 is larger than the cross-sectional area ofthe second region X2. Further, the volume of the first region X1 islarger than the volume of the second region X2 when viewed in the radialdirection in the range where the magnet unit 42 of the rotor 40 and thestator winding 51 overlap.

Moreover, when the rotor 40 and the stator 50 are a magnetic circuitcomponent assembly, in the housing 30, the first region X1 radiallyinside from the inner peripheral surface of the magnetic circuitcomponent assembly has a larger volume than that of the second region X2between the inner peripheral surface of the magnetic circuit componentassembly and the housing 30 in the radial direction.

Next, the configurations of the rotor 40 and the stator 50 will bedescribed in more detail.

Generally, as a structure of a stator in a rotating electric machine, astructure is known in which a stator core made of a laminated steelsheet and forming an annular shape is provided with a plurality of slotsin the circumferential direction, and a stator winding is wound in theslots. Specifically, the stator core has a plurality of teeth extendingin the radial direction from a yoke at predetermined intervals, andslots are formed between the teeth adjacent to each other in thecircumferential direction. In addition, for example, a plurality oflayers of conductors are housed in the slots in the radial direction,and the stator winding is composed of the conductors.

However, in the above-mentioned stator structure, when the statorwinding is energized, magnetic saturation occurs in the teeth portion ofthe stator core as the magnetomotive force of the stator windingincreases, which may limit the torque density of the rotating electricmachine. That is, in the stator core, it is considered that magneticsaturation occurs when the rotating magnetic flux generated by theenergization of the stator winding is concentrated on the teeth.

Further, generally, as a configuration of an IPM (Interior PermanentMagnet) rotor in a rotating electric machine, a permanent magnet isarranged on the d-axis in the d-q coordinate system and a rotor core isarranged on the q-axis. In such a case, the stator winding near thed-axis is excited, and thus the exciting magnetic flux flows from thestator to the q-axis of the rotor according to Fleming's law. It isconsidered that this causes a wide range of magnetic saturation in theq-axis core portion of the rotor.

FIG. 7 is a torque line diagram illustrating a relation between anampere-turn [AT] indicating the magnetomotive force of a stator windingand a torque density [Nm/L]. The broken line indicates thecharacteristics of a general IPM rotor type rotating electric machine.As illustrated in FIG. 7, in a general rotating electric machine, byincreasing the magnetomotive force in the stator, magnetic saturationoccurs in two places, the teeth portion between the slots and the q-axiscore portion, which limits the increase in torque. As described above,in the general rotating electric machine, the ampere-turn design valueis limited by A1.

Accordingly, in the present embodiment, in order to eliminate thelimitation caused by magnetic saturation, the rotating electric machine10 is provided with the following configuration. In other words, as afirst measure, in order to eliminate the magnetic saturation that occursin the teeth of the stator core in the stator, a slotless structure isadopted in the stator 50, and in order to eliminate the magneticsaturation that occurs in the q-axis core portion of the IPM rotor, anSPM (Surface Permanent Magnet) rotor is adopted. According to the firstmeasure, it is possible to eliminate the above-mentioned two parts wheremagnetic saturation occurs, but it is considered that the torque in thelow current region is reduced (see the alternate long and short dashline in FIG. 7). Therefore, as a second measure, in order to recover thetorque decrease by increasing the magnetic flux of the SPM rotor, in themagnet unit 42 of the rotor 40, a polar anisotropic structure in whichthe magnet magnetic path is lengthened to increase the magnetic force isadopted.

Further, as a third measure, in the coil side section 53 of the statorwinding 51, a flat conductor structure in which the radial thickness ofthe stator 50 of the conductor is reduced is adopted to recover thetorque decrease. Here, it is conceivable that a larger eddy current isgenerated in the stator winding 51 facing the magnet unit 42 due to theabove-mentioned polar anisotropic structure in which the magnetic forceis increased. However, according to the third measure, since the flatconductor structure is thin in the radial direction, it is possible tosuppress the generation of eddy current in the radial direction in thestator winding 51. As described above, according to each of these firstto third configurations, as illustrated by the solid line in FIG. 7, byadopting a magnet with a high magnetic force, it is expected that thetorque characteristics will be significantly improved, and at the sametime, the concern about the generation of a large eddy current that mayoccur due to the magnet with a high magnetic force also can be improved.

Furthermore, as a fourth measure, a magnet unit having a magnetic fluxdensity distribution close to a sine wave is adopted by utilizing apolar anisotropic structure. According to this, the sine wave matchingrate can be increased by pulse control or the like described below toincrease the torque, and since the magnetic flux changes more slowlythan the radial magnet, the eddy current loss (copper loss due to eddycurrent: eddy current loss) can also be further suppressed.

Hereinafter, the sine wave matching rate will be described. The sinewave matching rate can be obtained by comparing the measured waveform ofthe surface magnetic flux density distribution measured by tracing thesurface of the magnet with a magnetic flux probe and the sine wavehaving the same period and peak value. In addition, the ratio of theamplitude of the primary waveform, which is the fundamental wave of therotating electric machine, to the amplitude of the actually measuredwaveform, that is, the amplitude of the fundamental wave plus otherhigher harmonic components, corresponds to the sine wave matching rate.As the sine wave matching rate increases, the waveform of the surfacemagnetic flux density distribution approaches a sine wave shape. Inaddition, when a primary sine wave current is supplied from the inverterto a rotating electric machine equipped with a magnet having an improvedsine wave matching rate, the waveform of the surface magnetic fluxdensity distribution of the magnet is close to the sine wave shape, andcorrelatively, can generate a large torque. Moreover, the surfacemagnetic flux density distribution may be estimated by a method otherthan an actual measurement, for example, an electromagnetic fieldanalysis using Maxwell's equations.

Further, as a fifth measure, the stator winding 51 has a wire conductorstructure in which a plurality of wires are gathered and bundled.According to this, since the wires are connected in parallel, a largecurrent can flow, and the cross-sectional area of each wire is small,the eddy current generated by the conductors that spread in thecircumferential direction of the stator 50 in the flat conductorstructure can be suppressed more effectively than thinning in the radialdirection by the third measure. In addition, by forming a structure inwhich a plurality of wires are twisted together, for the magnetomotiveforce from the conductor, it is possible to cancel the eddy current withrespect to the magnetic flux generated by the right-handed screw rule inthe current energizing direction.

In this way, if the fourth and fifth measures are further added, thetorque can be increased while adopting the second measure, a magnet witha high magnetic force, while suppressing the eddy current loss caused bythe high magnetic force.

Hereinafter, the slotless structure of the stator 50 described above,the flat conductor structure of the stator winding 51, and the polaranisotropic structure of the magnet unit 42 will be individuallydescribed. Here, first, the slotless structure of the stator 50 and theflat conductor structure of the stator winding 51 will be described.FIG. 8 is a cross-sectional view of the rotor 40 and the stator 50, andFIG. 9 is a view illustrating a part of the rotor 40 and the stator 50illustrated in FIG. 8 in an enlarged manner. FIG. 10 is across-sectional view illustrating a cross section of the stator 50 alonga line X-X of FIG. 11, and FIG. 11 is a cross-sectional viewillustrating a vertical cross section of the stator 50. Further, FIG. 12is a perspective view of the stator winding St. Note that FIGS. 8 and 9illustrate the magnetization direction of the magnet in the magnet unit42 with arrows.

As illustrated in FIGS. 8 to 11, the stator core 52 has a cylindricalshape in which a plurality of electromagnetic steel sheets are laminatedin the axial direction and has a predetermined thickness in the radialdirection, and the stator winding 51 is assembled on the radiallyoutside that is the rotor 40 side. In the stator core 52, the outerperipheral surface on the rotor 40 side is a conductor installationsection (conductor area). The outer peripheral surface of the statorcore 52 has a curved surface without unevenness, and a plurality ofconductor groups 81 are arranged at predetermined intervals in thecircumferential direction on the outer peripheral surface thereof. Thestator core 52 functions as a back yoke that is a part of a magneticcircuit for rotating the rotor 40. In this case, teeth (that is, an ironcore) made of a soft magnetic material are not provided between each ofthe two conductor groups 81 adjacent to each other in thecircumferential direction (that is, a slotless structure). In thepresent embodiment, the resin material of the sealing member 57 isinserted into a void 56 of each of the conductor groups 81. That is, inthe stator 50, the interconductor member provided between the respectiveconductor groups 81 in the circumferential direction is configured asthe sealing member 57 which is a non-magnetic material. In a statebefore sealing of the sealing member 57, on the outer side of the statorcore 52 in the radial direction, the conductor groups 81 arerespectively arranged at predetermined intervals in the circumferentialdirection with the void 56, which is an inter-conductor region,interposed therebetween. As a result, the stator 50 having a slotlessstructure is constructed. In other words, each conductor group 81 iscomposed of two conductors (conductor) 82 described below, and only anon-magnetic material occupies a region between the two conductor groups81 adjacent to each other in the circumferential direction of the stator50. The non-magnetic material includes a non-magnetic gas such as air, anon-magnetic liquid, and the like in addition to the sealing member 57.Moreover, in the following, the sealing member 57 is also referred to asan inter-conductor member (conductor-to-conductor member).

Moreover, a configuration in which the teeth are provided between theconductor groups 81 arranged in the circumferential direction isconsidered to be a configuration in which the teeth have a predeterminedthickness in the radial direction and a predetermined width in thecircumferential direction, and thus a part of a magnetic circuit, thatis, a magnet magnetic path is formed between the conductor groups 81. Inthis respect, it can be said that a configuration in which the teeth arenot provided between the respective conductor groups 81 is aconfiguration in which the above-mentioned magnetic circuit is notformed.

As illustrated in FIG. 10, the stator winding (i.e., armature winding)51 is formed so as to have a predetermined thickness T2 (hereinafter,also referred to as a first dimension) and a width W2 (hereinafter, alsoreferred to as a second dimension). The thickness T2 is the shortestdistance between the outer surface and the inner surface facing eachother in the radial direction of the stator winding 51. The width W2 isthe circumferential length of the stator winding 51 of a part of thestator winding 51 which functions as one of the polyphase of the statorwinding 51 (in the example, three phases: three phases of U phase, Vphase and W phase or three phases of X phase, Y phase and Z phase).Specifically, in FIG. 10, in a case where two conductor groups 81adjacent to each other in the circumferential direction function as oneof the three phases, for example, the U phase, the width W2 is from oneend to the other of the two conductor groups 81 in the circumferentialdirection. In addition, the thickness T2 is smaller than the width W2.

Moreover, the thickness T2 is preferably smaller than the total widthdimension of the two conductor groups 81 existing in the width W2.Further, if the cross-sectional shape of the stator winding 51 (morespecifically, the conductor wire 82) is a perfect circle, an ellipse, ora polygon, in the cross sections of the conductor wire 82 along theradial direction of the stator 50, the maximum length in the radialdirection of the stator 50 may be W12, and the maximum length in thecircumferential direction of the stator 50 may be W11.

As illustrated in FIGS. 10 and 11, the stator winding 51 is sealed bythe sealing member 57 made of a synthetic resin material as a sealingmaterial (molding material). That is, the stator winding 51 is moldedtogether with the stator core 52 by the molding material. The resin canbe regarded as a non-magnetic substance or an equivalent of thenon-magnetic substance as Bs=0.

Looking at the cross section of FIG. 10, the sealing member 57 isprovided between the respective conductor groups 81, that is, the void56 is filled with the synthetic resin material, and with this sealingmember 57, an insulating member is interposed between the respectiveconductor groups 81. That is, the sealing member 57 functions as aninsulating member in the void 56. The sealing member 57 is provided onthe radial outside of the stator core 52 in a range including all of theconductor groups 81, that is, in a range in which the radial thicknessdimension is larger than the radial thickness dimension of eachconductor group 81.

Further, when viewed in the vertical cross section of FIG. 11, thesealing member 57 is provided in a range including a turn section 84 ofthe stator winding 51. Inside the stator winding 51 in the radialdirection, the sealing member 57 is provided within a range including atleast a part of the end faces of the stator core 52 facing in the axialdirection. In this case, the stator winding 51 is resin-sealed almostentirely except for the ends of the phase winding of each phase, thatis, the connection terminals with the inverter circuit.

In the configuration in which the sealing member 57 is provided in arange including the end face of the stator core 52, the laminated steelsheet of the stator core 52 can be pressed inward in the axial directionby the sealing member 57. As a result, the laminated state of each steelsheet can be maintained with the use of the sealing member 57. Moreover,in the present embodiment, the inner peripheral surface of the statorcore 52 is not resin-sealed, but instead, the entire stator core 52including the inner peripheral surface of the stator core 52 may beresin-sealed.

In a case where the rotating electric machine 10 is used as a vehiclepower source, the sealing member 57 is preferably made of a highlyheat-resistant fluororesin, epoxy resin, PPS resin, PEEK resin, LCPresin, silicon resin, PAI resin, PI resin, or the like. Further,considering the linear expansion coefficient from the viewpoint ofsuppressing cracking due to the expansion difference, it is desirablethat the material is the same as that of the outer coating of theconductor of the stator winding 51. In other words, a silicon resinhaving a linear expansion coefficient that is generally more than doublethat of other resins is preferably excluded. Moreover, for electricproducts that do not have an engine that utilizes combustion, such aselectric vehicles, PPO resin, phenol resin, and FRP resin that have heatresistance of approximately 180° C. are also candidates. This does notapply in the field where the ambient temperature of the rotatingelectric machine is considered to be below 100° C.

The torque of the rotating electric machine 10 is proportional to themagnitude of the magnetic flux. Here, in a case where the stator corehas teeth, the maximum amount of magnetic flux in the stator is limiteddepending on the saturation magnetic flux density in the teeth, but in acase where the stator core does not have teeth, the maximum amount ofmagnetic flux in the stator is not limited. Therefore, the configurationis advantageous in increasing the energization current for the statorwinding 51 to increase the torque of the rotating electric machine 10.

In the present embodiment, the inductance of the stator 50 is reduced byusing a structure (slotless structure) in which the stator 50 has noteeth. Specifically, in the stator of a general rotating electricmachine in which a conductor is housed in each slot partitioned by aplurality of teeth, the inductance is, for example, around 1 mH, whereasin the stator 50 of the present embodiment, the inductance is reduced toapproximately 5 to 60 pH. In the present embodiment, it is possible toreduce a mechanical time constant Tm by reducing the inductance of thestator 50 while using the rotating electric machine 10 having an outerrotor structure. That is, it is possible to reduce the mechanical timeconstant Tm while increasing the torque. Moreover, when the inertia isJ, the inductance is L, the torque constant is Kt, and the counterelectromotive force constant is Ke, the mechanical time constant Tm iscalculated by the following formula.

Tm=(J*L)/(Kt*Ke)

In this case, it can be confirmed that the mechanical time constant Tmis reduced by reducing the inductance L.

Each conductor group 81 on the radially outside the stator core 52 isconfigured by arranging a plurality of conductor wires 82 having a flatrectangular cross section side by side in the radial direction of thestator core 52. Each conductor wire 82 is arranged in a direction insuch a manner that “radial dimension<circumferential dimension” in thecross section. As a result, the thickness of each conductor group 81 isreduced in the radial direction. Further, the thickness in the radialdirection is reduced, and the conductor region extends flatly to theregion where the teeth have been conventionally, forming a flatconductor region structure. As a result, the increase in the amount ofheat generated of the conductor, which is a concern because thecross-sectional area becomes smaller due to the thinning, is suppressedby flattening in the circumferential direction and increasing thecross-sectional area of the conductor. Moreover, even if a plurality ofconductors are arranged in the circumferential direction and connectedin parallel, the conductor cross-sectional area of the conductor coatingis reduced, but the effect by the same reason can be obtained. Moreover,in the following, each conductor group 81 and each conductor wire 82will also be referred to as a conductive member.

Since there is no slot, in the stator winding 51 in the presentembodiment, the conductor region occupied by the stator winding 51 inone circumference in the circumferential direction can be designed to belarger than the conductor non-occupied region which the stator winding51 does not occupy. Moreover, in a conventional rotating electricmachine for vehicles, it is natural that the conductor region/conductornon-occupied region in one circumference in the circumferentialdirection of the stator winding is one or less. On the other hand, inthe present embodiment, each conductor group 81 is provided in such amanner that the conductor region is equal to the conductor non-occupiedregion or the conductor region is larger than the conductor non-occupiedregion. Here, as illustrated in FIG. 10, when the conductor region inwhich the conductor wire 82 (that is, a straight section 83 describedbelow) is arranged in the circumferential direction is WA and the regionbetween the adjacent conductor wires 82 is WB, the region WA is largerthan the interconductor region WB in the circumferential direction.

As a configuration of the conductor group 81 in the stator winding 51,the radial thickness dimension of the conductor group 81 is smaller thanthe circumferential width dimension for one phase in one magnetic pole.In other words, a configuration in which the conductor group 81 iscomposed of two layers of conductor wires 82 in the radial direction andtwo conductor groups 81 are provided in the circumferential directionfor one phase in one magnetic pole fulfills “Tc*2<Wc*2” when the radialthickness dimension of each conductor wire 82 is Tc, and thecircumferential width dimension of each conductor wire 82 is Wc.Moreover, as another configuration, a configuration in which theconductor group 81 is composed of two layers of conductor wires 82 andone conductor group 81 is provided in the circumferential direction forone phase in one magnetic pole preferably fulfills a relation “Tc*2<We”.In short, the conductor section (conductor group 81) arranged atpredetermined intervals in the circumferential direction in the statorwinding 51 has a radial thickness dimension that is smaller than thecircumferential width dimension for one phase in one magnetic pole.

In other words, it is preferable that the radial thickness dimension Tcof each conductor wire 82 is smaller than the circumferential widthdimension Wc. Furthermore, a radial thickness dimension (2Tc) in theradial direction of the conductor group 81 composed of two layers ofconductors 82, that is, a radial thickness dimension (2Tc) in thecircumferential direction of the conductor group 81 is preferablysmaller than the width dimension We.

The torque of the rotating electric machine 10 is substantiallyinversely proportional to the radial thickness of the stator core 52 ofthe conductor group 81. In this regard, the thickness of the conductorgroup 81 is reduced on the radial outside of the stator core 52, whichis advantageous in increasing the torque of the rotating electricmachine 10. The reason is that the magnetic resistance can be lowered byreducing the distance from the magnet unit 42 of the rotor 40 to thestator core 52 (that is, the distance of the iron-free portion).According to this, the interlinkage magnetic flux of the stator core 52by the permanent magnet can be increased, and the torque can beincreased.

Further, by reducing the thickness of the conductor group 81, even ifthe magnetic flux leaks from the conductor group 81, it is easilycollected by the stator core 52, and the magnetic flux can be preventedfrom not being effectively used for improving torque and leaking to theoutside. That is, it is possible to suppress a decrease in magneticforce due to magnetic flux leakage, and it is possible to increase theinterlinkage magnetic flux of the stator core 52 by the permanent magnetto increase the torque.

The conductor wire (conductor) 82 is composed of a coated conductor inwhich the surface of the conductor (conductor body) 82 a is coated withan insulating coating 82 b, and insulation is ensured between theconductor wires 82 that overlap each other in the radial direction andbetween the conductor wires 82 and the stator core 52, respectively.This insulating coating 82 b is composed of a coating if a wire 86described below is a self-fusion coated wire, or an insulating memberlaminated separately from the coating of the wire 86. Moreover, eachphase winding composed of the conductor wire 82 retains the insulatingproperty by the insulating coating 82 b except for the exposed portionfor connection. The exposed portion is, for example, an input/outputterminal portion or a neutral point portion in the case of a star-shapedconnection. In the conductor group 81, the conductor wires 82 adjacentto each other in the radial direction are fixed to each other with theuse of resin fixing or a self-fusion coated wire. As a result,dielectric breakdown, vibration, and sound due to the friction of theconductor wires 82 against each other are suppressed.

In the present embodiment, the conductor 82 a is configured as anaggregate of a plurality of wires (wire) 86. Specifically, asillustrated in FIG. 13, the conductor 82 a is formed in a twisted stateby twisting a plurality of wires 86. Further, as illustrated in FIG. 14,the wires 86 are configured as a composite in which thin fibrousconductive materials 87 are bundled. For example, the wire 86 is acomposite of CNT (carbon nanotube) fibers, and as the CNT fiber, a fibercontaining boron-containing fine fibers in which at least a part ofcarbon is replaced with boron is used. As the carbon-based fine fiber, avapor-grown carbon fiber (VGCF) or the like can be used in addition tothe CNT fiber, but it is preferable to use the CNT fiber. Moreover, thesurface of the wire 86 is covered with a polymer insulating layer suchas enamel. Further, it is preferable that the surface of the wire 86 iscovered with a so-called enamel coating made of a polyimide film or anamide-imide film.

The conductor wire 82 constitutes an n-phase winding in the statorwinding 51. In addition, the respective wires 86 of the conductor wire82 (that is, the conductor 82 a) are adjacent to each other in contactwith each other. In the conductor wire 82, the winding conductor has aportion formed by twisting the plurality of wires 86 at one or moreplaces in a phase, and the resistance value among the twisted wires 86is larger than the resistance value of each wire 86 per se. In otherwords, if each of the two adjacent wires 86 has a first electricalresistivity in its adjacent direction and each of the wires 86 has asecond electrical resistivity in its length direction, then the firstelectrical resistivity is larger than the second electrical resistivity.Moreover, the conductor wire 82 may be formed of the plurality of wires86, and may be an aggregate of wires covering the plurality of wires 86by an insulating member having an extremely high first electricalresistivity. Further, the conductor 82 a of the conductor wire 82 iscomposed of a plurality of twisted wires 86.

Since the conductor 82 a is configured by twisting the plurality ofwires 86, it is possible to suppress the generation of the eddy currentin the respective wires 86 and reduce the eddy current in the conductor82 a. Further, since each wire 86 is twisted, portions where themagnetic field application directions are opposite to each other aregenerated in one wire 86, and the counter electromotive voltage iscanceled out. Therefore, the eddy current can also be reduced. Inparticular, by forming the wire 86 with the fibrous conductive material87, it is possible to make the wire thinner and to significantlyincrease the number of twists, and it is possible to more preferablyreduce the eddy current.

Moreover, the method for insulating the wires 86 from each other here isnot limited to the above-mentioned polymer insulating film, and may be amethod for making it difficult for current to flow between the twistedwires 86 by utilizing contact resistance. That is, if the resistancevalue between the twisted wires 86 is larger than the resistance valueof the wire 86 per se, the above effect can be obtained by the potentialdifference generated due to the difference in the resistance values. Forexample, by using the manufacturing equipment for creating the wire 86and the manufacturing equipment for making the stator 50 (armature) ofthe rotating electric machine 10 as separate non-continuous equipment,the wire 86 can be oxidized due to the movement time, work interval, andthe like, and the contact resistance can be increased, which issuitable.

As described above, the conductor wires 82 have a flat rectangular crosssection and are arranged side by side in the radial direction, and forexample, a plurality of wires 86 covered with a self-fusion coated wirehaving a fusion layer and an insulating layer is assembled in a twistedstate, and the fusion layers are fused to maintain the shape of theconductor wires 82. Moreover, the wires having no fusion layer or thewires with the self-fusion coated wire may be twisted and solidified andmolded into a desired shape with a synthetic resin or the like. When thethickness of the insulating coating 82 b in the conductor wire 82 is setto, for example, 80 μm to 100 μm and is set to be thicker than the filmthickness (5 to 40 μm) of a commonly used conductor, even if aninsulating paper or the like is not interposed between the conductorwire 82 and the stator core 52, the insulating property between the twocan be ensured.

Further, it is desirable that the insulating coating 82 b has higherinsulating performance than that of the insulating layer of the wire 86and is configured to be able to insulate between phases. For example,when the thickness of the polymer insulating layer of the wire 86 is setto, for example, approximately 5 μm, it is desirable that the thicknessof the insulating coating 82 b of the conductor wire 82 is set toapproximately 80 μm to 100 μm, and thus insulation between phases can bepreferably performed.

Further, the conductor wire 82 may have a configuration in which aplurality of wires 86 are bundled without being twisted. That is, theconductor wire 82 may have any of a configuration in which a pluralityof wires 86 are twisted in the total length, a configuration in which aplurality of wires 86 are twisted in a part of the total length, and aconfiguration in which a plurality of wires 86 are bundled without beingtwisted anywhere in the total length. In summary, each conductor wire 82constituting the conductor section is a wire aggregate in which aplurality of wires 86 are bundled and the resistance value between thebundled wires is larger than the resistance value of the wire 86 per se.

Each conductor wire 82 is bent and formed so as to be arranged in apredetermined arrangement pattern in the circumferential direction ofthe stator winding 51, and as a result, a phase winding for each phaseis formed as the stator winding 51. As illustrated in FIG. 12, in thestator winding 51, the coil side section 53 is formed by the straightsection 83 of each conductor wire 82 extending linearly in the axialdirection, and the coil ends 54 and 55 are formed by the turn section 84protruding to both outsides from the coil side section 53 in the axialdirection. Each conductor wire 82 is configured as a series of wavewinding-shaped conductors by alternately repeating the straight section83 and the turn section 84. The straight sections 83 are arranged atpositions facing the magnet unit 42 in the radial direction, andin-phase straight sections 83 arranged at positions on the axially outerside of the magnet unit 42 at predetermined intervals are connected toeach other by the turn section 84. Note that the straight section 83corresponds to a “magnet facing section”.

In the present embodiment, the stator winding 51 is wound in an annularshape by distributed winding, in this case, in the coil side section 53,straight sections 83 are arranged in the circumferential direction atintervals corresponding to one pole pair of the magnet unit 42 for eachphase, and in the coil ends 54 and 55, the respective straight sections83 for each phase are connected to each other by the turn section 84formed in a substantially V shape. The directions of the currents of thestraight section 83 that are paired corresponding to one-pole pair areopposite to each other. Further, the combination of the pair of straightsections 83 connected by the turn section 84 is different between onecoil end 54 and the other coil end 55, and the connections at the coilends 54 and 55 are repeated in the circumferential direction, and thusthe stator winding 51 is formed in a substantially cylindrical shape.

More specifically, the stator winding 51 constitutes a winding for eachphase with the use of two pairs of conductor wires 82 for each phase,and one three-phase winding (U-phase, V-phase, W-phase) and the otherthree-phase winding (X-phase, Y-phase, Z-phase) of the stator winding 51are provided in two layers inside and outside in the radial direction.In this case, if the number of phases of the stator winding 51 is S (6in the case of the example) and the number of conductor wires 82 perphase is m, then 2*S*m=2Sm conductor wires 82 will be formed for eachpole pair. In the present embodiment, since the number of phases S is 6,the number of m is 4, and an 8-pole pair (16 poles) rotating electricmachine is used, 6*4*8=192 conductor wires 82 are arranged in thecircumferential direction of the stator core 52.

In the stator winding 51 illustrated in FIG. 12, in the coil sidesection 53, the straight sections 83 are arranged so as to overlap intwo layers adjacent in the radial direction, and in the coil ends 54 and55, the turn sections 84 extend in directions opposite to each other inthe circumferential direction, from each of the straight sections 83overlapping in the radial direction. That is, in the respectiveconductor wires 82 adjacent to each other in the radial direction, thedirections of the turn sections 84 are opposite to each other except forthe ends of the stator winding 51.

Here, the winding structure of the conductor wire 82 in the statorwinding 51 will be specifically described. In the present embodiment, aplurality of conductor wires 82 formed by wave winding are provided soas to be stacked in a plurality of layers (for example, two layers)adjacent to each other in the radial direction. FIGS. 15A and 15B arediagrams illustrating a form of each conductor wire 82 in an nth layer,FIG. 15A illustrates a shape of the conductor wire 82 seen from the sideof the stator winding 51, and FIG. 15B illustrates a shape of theconductor wire 82 seen from one side in the axial direction of thestator winding 51. Moreover, in FIG. 15A and FIG. 15B, the positionswhere the conductor group 81 is arranged are illustrated as D1, D2, D3,. . . , respectively. Further, for convenience of explanation, onlythree conductor wires 82 are illustrated, which are referred to as afirst conductor 82_A, a second conductor 82_B, and a third conductor82_C.

In each of the conductors 82_A to 82_C, the straight sections 83 are allarranged at the nth layer position, that is, at the same position in theradial direction, and the straight sections 83 separated from each otherby 6 positions (3*m pairs) in the circumferential direction areconnected to each other by the turn section 84. In other words, in eachof the conductors 82_A to 82_C, on the same circle centered on the shaftcenter of the rotor 40, both ends of the seven straight sections 83arranged adjacent to each other in the circumferential direction of thestator winding 51 are connected to each other by one turn section 84.For example, in the first conductor 82_A, a pair of straight sections 83are arranged at D1 and D7, respectively, and the pair of straightsections 83 are connected to each other by an inverted V-shaped turnsection 84. Further, the other conductors 82_B and 82_C are arranged inthe same nth layer with their circumferential positions shifted by one.In this case, since the conductors 82_A to 82_C are all arranged in thesame layer, it is conceivable that the turn sections 84 might interferewith each other. Therefore, in the present embodiment, an interferenceavoidance section is formed in the turn section 84 of each of theconductors 82_A to 82_C with a part thereof offset in the radialdirection.

Specifically, the turn section 84 of each of the conductors 82_A to 82_Chas one tilted portion 84 a which is a portion extending in thecircumferential direction on the same circle (first circle), a topportion 84 b that shifts from the tilted portion 84 a radially inward(upper side in FIG. 15B) of the same circle and reaches another circle(second circle), an tilted portion 84 c that extends in thecircumferential direction on the second circle, and a return portion 84d that returns from the first circle to the second circle. The topportion 84 b, tilted portion 84 c, and return portion 84 d correspond tothe interference avoidance section. Moreover, the tilted portion 84 cmay be configured to shift outward in the radial direction with respectto the tilted portion 84 a.

That is, the turn sections 84 of the conductors 82_A to 82_C have atilted portion 84 a on one side and a tilted portion 84 c on the otherside on both sides of the top portion 84 b which is a central positionin the circumferential direction. The radial positions of the tiltedportions 84 a and 84 c (the position in the front-rear direction of theplane of FIG. 15A and the position in the up-down direction in FIG. 15B)are different from each other. For example, the turn section 84 of thefirst conductor 82_A extends along the circumferential direction with aD1 position of the nth layer as the start point position, bends in theradial direction (for example, inward in the radial direction) at thetop portion 84 b which is the central position in the circumferentialdirection, and then bends again in the circumferential direction,thereby extending along the circumferential direction again, and furtherbends in the radial direction (for example, outside in the radialdirection) again at the return portion 84 d, thereby reaching a D7position of the nth layer, which is the end point position.

According to the above configuration, in the conductors 82_A to 82_C,each tilted portion 84 a on one side is arranged vertically in the orderof the first conductor 82_A, the second conductor 82_B, and the thirdconductor 82_C from the top, and at the top portion 84 b, the top andbottom of each conductor 82_A to 82_C are interchanged, and each tiltedportion 84 c on the other side is arranged vertically in the order ofthe third conductor 82_C, the second conductor 82_B, and the firstconductor 82_A from the top. Therefore, the respective conductors 82_Ato 82_C can be arranged in the circumferential direction withoutinterfering with each other.

Here, in a configuration in which a plurality of conductor wires 82 arestacked in the radial direction to form a conductor group 81, it ispreferable that the turn section 84 connected to the straight section 83on the radially inside and the turn section 84 connected to the straightsection 83 on the radial outside of the respective straight sections 83of the plurality of layers are arranged so as to be radially separatedfrom each of the straight sections 83. Further, when the conductor wires82 of a plurality of layers are bent to the same side in the radialdirection near the end of the turn section 84, that is, the boundaryportion with the straight section 83, it is preferable that theinsulating property is not impaired due to the interference between theconductor wires 82 of the adjacent layers.

For example, in D7 to D9 of FIG. 15A and FIG. 15B, the respectiveconductor wires 82 overlapping in the radial direction are respectivelybent in the radial direction at the return portion 84 d of the turnsection 84. In this case, as illustrated in FIG. 16, it is preferablethat the radius of curvature of the bent portion is different betweenthe conductor wire 82 of the nth layer and the conductor wire 82 of then+1 layer. Specifically, a radius of curvature R1 of the conductor wire82 on the radially inside (nth layer) is made smaller than a radius ofcurvature R2 of the conductor wire 82 on the radially outside (n+1thlayer).

Further, it is preferable that the radial shift amount is differentbetween the nth layer conductor wire 82 and the n+1th layer conductorwire 82. Specifically, a shift amount S1 of the conductor wire 82 on theradially inside (nth layer) is made larger than a shift amount S2 of theconductor wire 82 on the radially outside (n+1th layer).

With the above configuration, mutual interference of the respectiveconductor wires 82 can be suitably avoided even when the respectiveconductor wires 82 overlapping in the radial direction are bent in thesame direction. As a result, good insulating properties can be obtained.

Next, the structure of the magnet unit 42 in the rotor 40 will bedescribed. In the present embodiment, it is assumed that the magnet unit42 is made of a permanent magnet, has a residual magnetic flux densityBr=1.0 [T], and has an intrinsic coercive force Hcj=400 [kA/m] or more.In short, the permanent magnet used in this embodiment is a sinteredmagnet obtained by sintering and solidifying a granular magneticmaterial, and the intrinsic coercive force Hcj on the J-H curve is 400[kA/m] or more, and the residual magnetic flux density Br is 1.0 [T] ormore. When 5000 to 10000 [AT] is applied by interphase excitation, if apermanent magnet with a length of 25 [mm] is used in the magnetic lengthof one pole pair, that is, the N pole and the S pole, in other words,the path of the magnetic flux flowing between the N pole and the S pole,then Hcj=10000 [A], indicating that demagnetization is not performed.

In other words, the magnet unit 42 has a saturation magnetic fluxdensity Js of 1.2 [T] or more, a crystal particle size of 10 [μm] orless, and Js*α of 1.0 [T] or higher when the orientation ratio is α.

The magnet unit 42 will be supplemented below. The magnet unit 42(magnet) is characterized in that 2.15 [T]≥Js≥1.2 [T]. In other words,examples of the magnet used in the magnet unit 42 include NdFe11TiN,Nd2Fe14B, Sm2Fe17N3, and FeNi magnets having L10 type crystals.Moreover, configurations such as SmCo5 which is usually calledsamarium-cobalt, FePt, Dy2Fe14B, and CoPt cannot be used. Note that,like the same type of compounds such as Dy2Fe14B and Nd2Fe14B, in somecases, even a magnet that generally uses dysprosium which is a heavyrare earth to have a high coercive force of Dy while slightly losing thehigh Js characteristics of neodymium fulfills 2.15 [T]≥Js≥1.2 [T], themagnet can be employed in this case as well. In such a case, the magnetis referred to as ([Nd1−xDyx]2Fe14B), for example. Furthermore, themagnet can be achieved by two or more types of magnets having differentcompositions, for example, magnets made of two or more types ofmaterials such as FeNi plus Sm2Fe17N3, and for example, the magnet canalso be achieved by a mixed magnet in which a small amount of Js<1 [T],for example, Dy2Fe14B is mixed with a magnet of Nd2Fe14B havingsufficient value of Js, i.e. J_(s)=1.6 [T], and the coercive force isincreased.

Further, for rotating electric machines that operate at temperaturesoutside the range of human activity, for example, 60° C. or higher,which exceeds the temperature of a desert, for example, in vehicle motorapplications where the temperature inside the vehicle is close to 80° C.in summer, it is desirable to contain the components of FeNi andSm2Fe17N3, which have a particularly small temperature dependencecoefficient. This is because the motor characteristics differ greatlydepending on the temperature dependence coefficient in the motoroperation from a temperature state close to −40° C. in Northern Europe,which is within the range of human activity, to 60° C. or higher, whichexceeds the desert temperature mentioned above, or to a heat resistanttemperature of coil enamel coating approximately 180-240° C., and thusit becomes difficult to perform optimum control with the same motordriver. If the aforementioned FeNi having 10 type crystals, Sm2Fe17N3,or the like is used, the burden on the motor driver can be suitablyreduced due to its characteristic of having a temperature dependencecoefficient of less than half that of Nd2Fe14B.

Additionally, the magnet unit 42 is characterized in that the size ofthe particle diameter in the fine powder state before orientation is 10μm or less and the single magnetic domain particle diameter or more byusing the aforementioned magnet blending. In magnets, the coercive forceis increased by miniaturizing the powder particles to the order ofseveral hundred nm. Therefore, in recent years, powder as fine aspossible has been used. However, if they are made too fine, the BHproduct of the magnet will drop due to oxidation or the like, and thus asingle magnetic domain particle diameter or larger is preferable. It isknown that the coercive force increases by the miniaturization when theparticle diameter is up to the single magnetic domain particle diameter.Moreover, the size of the particle diameter that has been described hereis the size of the particle diameter in the fine powder state at thetime of the orientation process in the magnet manufacturing process.

Furthermore, each of the first magnet 91 and the second magnet 92 of themagnet unit 42 is a sintered magnet formed by so-called sintering, inwhich magnetic powder is baked and hardened at a high temperature. Inthis sintering, when the saturation magnetization Js of the magnet unit42 is 1.2 T or more, the crystal grain diameter of the first magnet 91and the second magnet 92 is 10 μm or less, and the orientation ratio isa, sintering is performed in such a manner that Js*a fulfills acondition of 1.0 T (tesla) or more. Further, each of the first magnet 91and the second magnet 92 is sintered so as to fulfill the followingconditions. In addition, the orientation is performed in the orientationprocess in the manufacturing process, the orientation ratio is differentfrom the definition of the magnetic force direction by the magnetizingprocess of the isotropic magnet. With the saturation magnetization Js ofthe magnet unit 42 of the present embodiment is 1.2 T or more, a highorientation ratio is set in such a manner that the orientation ratio αof the first magnet 91 and the second magnet 92 is Jr≥Js*α≥1.0 [T].Moreover, the orientation ratio α referred to here is that, in a casewhere in each of the first magnet 91 and the second magnet 92, forexample, there are six axes of easy magnetization, if five of the axesface a direction A10 in the same direction and the remaining one faces adirection B10 tilted 90 degrees with respect to the direction A10,α=5/6, and if the remaining one faces the direction B10 tilted 45degrees with respect to the direction A10, the component for theremaining one facing the direction A10 is cos 45°=0.707, and thusα=(5+0.707)/6. In this example, the first magnet 91 and the secondmagnet 92 are formed by sintering, but if the above conditions arefulfilled, the first magnet 91 and the second magnet 92 may be molded byanother method. For example, a method for forming an MQ3 magnet or thelike can be employed.

In this embodiment, since a permanent magnet whose axis of easymagnetization is controlled by orientation is used, the magnetic circuitlength inside the magnet can be made longer than the magnetic circuitlength of a linearly oriented magnet that conventionally produces 1.0[T] or more. That is, the magnetic circuit length per pole pair can beachieved with a small amount of magnets, and the reversibledemagnetization range can be maintained even when exposed to harsh highthermal conditions compared to the conventional design using linearlyoriented magnets. Further, the discloser of the present application hasfound a configuration in which characteristics similar to those of apolar anisotropic magnet can be obtained even with the use of a magnetof the prior art.

Note that, the axis of easy magnetization refers to a crystalorientation that is easily magnetized in a magnet. The direction of theaxis of easy magnetization in the magnet is a direction in which theorientation ratio indicating the degree to which the directions of theaxes of easy magnetization are aligned is 50% or more, or a direction inwhich the orientation of the magnet is average.

As illustrated in FIGS. 8 and 9, the magnet unit 42 has an annular shapeand is provided inside the magnet holder 41 (specifically, radiallyinside the cylindrical section 43). The magnet unit 42 has a firstmagnet 91 and a second magnet 92, which are respectively polaranisotropic magnets and have different polarities from each other. Thefirst magnet 91 and the second magnet 92 are arranged alternately in thecircumferential direction. The first magnet 91 is a magnet that forms anN pole in a portion close to the stator winding 51, and the secondmagnet 92 is a magnet that forms an S pole in a portion close to thestator winding 51. The first magnet 91 and the second magnet 92 arepermanent magnets made of rare earth magnets such as neodymium magnets.

In each of the magnets 91 and 92, as illustrated in FIG. 9, in the knownd-q coordinate system, the magnetization direction extends in an areshape between the d-axis (direct-axis) which is the center of themagnetic pole and the q-axis (quadrature-axis) which is the magneticpole boundary between the N pole and the S pole (in other words, themagnetic flux density is 0 tesla). In each of the magnets 91 and 92, themagnetization direction is the radial direction of the annular magnetunit 42 on the d-axis side, and the magnetization direction of theannular magnet unit 42 is the circumferential direction on the q-axisside. Hereinafter, it will be described in more detail. As illustratedin FIG. 9, each of the magnets 91 and 92 has a first portion 250 and twosecond portions 260 located on both sides of the first portion 250 inthe circumferential direction of the magnet unit 42. In other words, thefirst portion 250 is closer to the d-axis than the second portion 260is, and the second portion 260 is closer to the q-axis than the firstportion 250 is. In addition, the magnet unit 42 is configured in such amanner that the direction of an axis of easy magnetization 300 of thefirst portion 250 is more parallel to the d-axis than the direction ofan axis of easy magnetization 310 of the second portion 260. In otherwords, the magnet unit 42 is configured in such a manner that an angleθ11 formed by the axis of easy magnetization 300 of the first portion250 and the d-axis is smaller than an angle θ12 formed by the axis ofeasy magnetization 310 of the second portion 260 and the q-axis.

More specifically, the angle θ11 is an angle formed by the d-axis andthe axis of easy magnetization 300 when the direction from the stator 50(armature) to the magnet unit 42 is positive on the d-axis. The angleθ12 is an angle formed by the q-axis and the axis of easy magnetization310 when the direction from the stator 50 (armature) to the magnet unit42 is positive on the q-axis. Both the angle θ11 and the angle θ12 are90° or less in this embodiment. Each of the axes of easy magnetization300 and 310 referred to here is defined by the following. If one axis ofeasy magnetization faces a direction A11 and the other axis of easymagnetization faces a direction B11 in each of the magnets 91 and 92,the absolute value (|cos θ|) of the cosine of the angle θ formed by thedirection A11 and the direction B11 is the axis of easy magnetization300 or the axis of easy magnetization 310.

That is, each of the magnets 91 and 92 has a different direction of theaxis of easy magnetization on the d-axis side (the portion near thed-axis) and the q-axis side (the portion near the q-axis), and on thed-axis side, the direction of the axis of easy magnetization is close tothe direction parallel to the d-axis, and on the q-axis side, thedirection of the easy magnetization axis is close to the directionorthogonal to the q-axis. In addition, an arc-shaped magnet magneticpath is formed in accordance with the direction of the axis of easymagnetization. Moreover, in each of the magnets 91 and 92, the axis ofeasy magnetization may be oriented parallel to the d-axis on the d-axisside, and the axis of easy magnetization may be oriented orthogonal tothe q-axis on the q-axis side

Further, in the magnets 91 and 92, of the peripheral surfaces of themagnets 91 and 92, the outer surface on the stator side on the stator 50side (lower side in FIG. 9) and the end face on the q-axis side in thecircumferential direction are magnetic flux acting surfaces which areinflow and outflow surfaces of magnetic flux, and a magnet magnetic pathis formed so as to connect these magnetic flux acting surfaces (theouter surface on the stator side and the end face on the q-axis side).

In the magnet unit 42, magnetic flux flows in an arc shape betweenadjacent N and S poles due to the magnets 91 and 92, and thus the magnetmagnetic path is longer than that of, for example, a radial anisotropicmagnet. Therefore, as illustrated in FIG. 17, the magnetic flux densitydistribution is close to a sine wave. As a result, unlike the magneticflux density distribution of the radial anisotropic magnet illustratedas a comparative example in FIG. 18, the magnetic flux can beconcentrated on the center side of the magnetic poles, and the torque ofthe rotating electric machine 10 can be increased. Further, it can beconfirmed that the magnet unit 42 of the present embodiment has adifference in the magnetic flux density distribution as compared with aconventional Halbach array magnet. Moreover, in FIGS. 17 and 18, thehorizontal axis represents an electrical angle and the vertical axisrepresents a magnetic flux density. Further, in FIGS. 17 and 18, 90° onthe horizontal axis indicates the d-axis (that is, the center of themagnetic pole), and 0° and 180° on the horizontal axis indicate theq-axis.

That is, according to the magnets 91 and 92 having the aboveconfiguration, the magnet magnetic flux on the d-axis is strengthenedand the change in magnetic flux near the q-axis is suppressed. As aresult, magnets 91 and 92 in which the change in surface magnetic fluxfrom the q-axis to the d-axis at each magnetic pole is gentle can bepreferably achieved.

The sine wave matching rate of the magnetic flux density distributionshould be, for example, a value of 40% or more. By doing so, it ispossible to reliably improve the amount of magnetic flux in the centralportion of the waveform as compared with the case of using a radiallyoriented magnet or a parallel oriented magnet having a sine wavematching rate of approximately 30%. Further, if the sine wave matchingrate is 60% or more, the amount of magnetic flux in the central portionof the waveform can be reliably improved as compared with the magneticflux concentrated array such as the Halbach array.

In the radial anisotropic magnet illustrated in FIG. 18, the magneticflux density changes steeply in the vicinity of the q-axis. The steeperthe change in magnetic flux density, the greater the eddy currentgenerated in the stator winding 51. Further, the change in magnetic fluxon the stator winding 51 side is also steep. On the other hand, in thepresent embodiment, the magnetic flux density distribution is a magneticflux waveform close to a sine wave. Therefore, the change in themagnetic flux density in the vicinity of the q-axis is smaller than thechange in the magnetic flux density of the radial anisotropic magnet. Asa result, the generation of eddy current can be suppressed.

In the magnet unit 42, a magnetic flux is generated in the vicinity ofthe d-axis (that is, the center of the magnetic pole) of each of themagnets 91 and 92 in a direction orthogonal to a magnetic flux actingsurface 280 on the stator 50 side, and the farther away from themagnetic flux acting surface 280 on the stator 50 side, the magneticflux forms an arc shape farther away from the d-axis. Further, themagnetic flux more orthogonal to the magnetic flux acting surfacebecomes stronger. In this respect, in the rotating electric machine 10of the present embodiment, since each conductor group 81 is thinned inthe radial direction as described above, the radial center position ofthe conductor group 81 approaches the magnetic flux acting surface ofthe magnet unit 42, and the stator 50 can receive a strong magnetmagnetic flux from the rotor 40.

Further, the stator 50 is provided with a cylindrical stator core 52 onthe radial inside of the stator winding 51, that is, on the sideopposite to the rotor 40 with the stator winding 51 therebetween.Therefore, the magnetic flux extending from the magnetic flux actingsurface of each of the magnets 91 and 92 is attracted to the stator core52 and orbits while using the stator core 52 as a part of the magneticpath. In this case, the direction and path of the magnet magnetic fluxcan be optimized.

The procedure for assembling the bearing unit 20, the housing 30, therotor 40, the stator 50, and the inverter unit 60 illustrated in FIG. 5will be described below as a method for manufacturing the rotatingelectric machine 10. Moreover, as illustrated in FIG. 6, the inverterunit 60 has a unit base 61 and an electric component 62, and each workprocess including the assembling process of the unit base 61 and theelectric component 62 will be described. In the following description,the assembly including the stator 50 and the inverter unit 60 isreferred to as a first unit, and the assembly including the bearing unit20, the housing 30 and the rotor 40 is referred to as a second unit.

This manufacturing process has

-   -   a first process for mounting the electric component 62 radially        inside the unit base 61,    -   a second process for mounting the unit base 61 radially inside        the stator 50 to manufacture the first unit,    -   a third process for inserting the fixing section 44 of the rotor        40 into the bearing unit 20 assembled to the housing 30 to        manufacture the second unit,    -   a fourth process for mounting the first unit radially inside the        second unit, and    -   a fifth process for fastening and fixing the housing 30 and the        unit base 61.

The execution order of each of these processes is the first process,second process, third process, fourth process, and fifth process.

According to the above manufacturing method, the bearing unit 20,housing 30, rotor 40, stator 50, and inverter unit 60 are assembled as aplurality of assemblies (subassemblies), and then the assemblies areassembled to each other. Therefore, ease of handling and completion ofinspection for each unit can be achieved, and a rational assembly linecan be constructed. Consequently, it is possible to easily cope withmulti-product production.

In the first process, a good thermal conductor having good thermalconductivity is attached to at least one of the radial inside of theunit base 61 and the radial outside of the electric component 62 bycoating, adhesion, or the like, and in that state, the electriccomponent 62 is preferably attached to the unit base 61. This makes itpossible to effectively transmit the heat generated by the semiconductormodule 66 to the unit base 61.

In the third process, the rotor 40 is preferably inserted whilemaintaining the coaxiality between the housing 30 and the rotor 40.Specifically, for example, using a jig for determining the position ofthe outer peripheral surface of the rotor 40 (outer peripheral surfaceof the magnet holder 41) or the inner peripheral surface of the rotor 40(inner peripheral surface of the magnet unit 42) with reference to theinner peripheral surface of the housing 30, the housing 30 and the rotor40 are assembled while sliding either the housing 30 or the rotor 40along the jig. As a result, heavy parts can be assembled withoutapplying an unbalanced load to the bearing unit 20, and the reliabilityof the bearing unit 20 is improved.

In the fourth process, it is preferable to assemble the first unit andthe second unit while maintaining the coaxiality between both units.Specifically, for example, using a jig for determining the position ofthe inner peripheral surface of the unit base 61 with reference to theinner peripheral surface of the fixing section 44 of the rotor 40, eachof the first unit and the second unit is assembled while sliding eitherone of them along the jig. As a result, it is possible to assemble therotor 40 and the stator 50 while preventing mutual interference witheach other between the minimum gaps, and therefore it is possible toeliminate defective products caused by assembly, such as damage to thestator winding 51 and chipping of permanent magnets.

The order of each of the above processes may also be the second process,third process, fourth process, fifth process, and first process. In thiscase, the delicate electric component 62 is assembled last, and thestress on the electric component 62 in the assembling process can beminimized.

Next, the configuration of the control system that controls the rotatingelectric machine 10 will be described. FIG. 19 is an electrical circuitdiagram of the control system of the rotating electric machine 10, andFIG. 20 is a functional block diagram illustrating control processing bya control device 110.

In FIG. 19, two sets of three-phase windings 51 a and 51 b areillustrated as the stator winding 51. The three-phase winding 51 aincludes a U-phase winding, a V-phase winding, and a W-phase winding,and the three-phase winding 51 b includes an X-phase winding, a Y-phasewinding, and a Z-phase winding. A first inverter 101 and a secondinverter 102, which correspond to power converters, are provided foreach of the three-phase windings 51 a and 51 b, respectively. Theinverters 101 and 102 are composed of a full bridge circuit having thesame number of upper and lower arms as the number of phases of the phasewindings, and the energization current is adjusted in each phase windingof the stator winding 51 by turning on/off a switch (semiconductorswitching element) provided on each arm.

A DC power supply 103 and a smoothing capacitor 104 are connected inparallel to each of the inverters 101 and 102. The DC power supply 103is composed of, for example, an assembled battery in which a pluralityof single batteries are connected in series. Moreover, each switch ofthe inverters 101 and 102 corresponds to the semiconductor module 66illustrated in FIG. 1 and the like, and the capacitor 104 corresponds tothe capacitor module 68 illustrated in FIG. 1 and the like.

The control device 110 includes a microcomputer composed of a CPU andvarious memories, and performs energization control by turning on/offeach switch in the inverters 101 and 102 on the basis of variousdetected information in the rotating electric machine 10 and requestsfor power running and power generation. The control device 110corresponds to the control device 77 illustrated in FIG. 6. The detectedinformation of the rotating electric machine 10 includes, for example, arotation angle (electrical angle information) of the rotor 40 detectedby an angle detector such as a resolver, a power supply voltage(inverter input voltage) detected by a voltage sensor, and anenergization current of each phase detected by a current sensor. Thecontrol device 110 generates and outputs an operation signal foroperating each switch of the inverters 101 and 102. Moreover, therequest for power generation is, for example, a request for regenerativedriving when the rotating electric machine 10 is used as a power sourcefor a vehicle.

The first inverter 101 includes a series connection body of an upper armswitch Sp and a lower arm switch Sn in three phases composed of the Uphase, V phase, and W phase. The high potential side terminal of theupper arm switch Sp of each phase is connected to the positive electrodeterminal of the DC power supply 103, and the low potential side terminalof the lower arm switch Sn of each phase is connected to the negativeelectrode terminal (ground) of the DC power supply 103. One ends of theU-phase winding, V-phase winding, and W-phase winding are connected tothe intermediate connection points between the upper arm switch Sp andthe lower arm switch Sn of each phase, respectively. These respectivephase windings are connected in a star-shape (Y-connected), and theother ends of the respective phase windings are connected to each otherat a neutral point.

The second inverter 102 has the same configuration as that of the firstinverter 101, and includes a series connection body of the upper armswitch Sp and the lower arm switch Sn in three phases composed of the Uphase, V phase, and W phase. The high potential side terminal of theupper arm switch Sp of each phase is connected to the positive electrodeterminal of the DC power supply 103, and the low potential side terminalof the lower arm switch Sn of each phase is connected to the negativeelectrode terminal (ground) of the DC power supply 103. One ends of theX-phase winding, Y-phase winding, and Z-phase winding are connected tothe intermediate connection points between the upper arm switch Sp andthe lower arm switch Sn of each phase, respectively. These respectivephase windings are connected in a star-shape (Y-connected), and theother ends of the respective phase windings are connected to each otherat a neutral point.

FIG. 20 illustrates current feedback control processing for controllingeach phase current of the U, V, and W phases, and current feedbackcontrol processing for controlling each phase current of the X, Y, and Zphases. Here, first, the control processing on the U, V, and W phaseside will be described.

In FIG. 20, a current command value setting unit 111 uses a torque-dqmap and sets a d-axis current command value and a q-axis current commandvalue on the basis of the power running torque command value or thepower generation torque command value for the rotating electric machine10 and an electric angular velocity ω obtained by time-differentiatingan electrical angle 9. Moreover, the current command value setting unit111 is commonly provided on the U, V, and W phase side and the X, Y, andZ phase side. Note that the power generation torque command value is,for example, a regenerative torque command value when the rotatingelectric machine 10 is used as a power source for a vehicle.

A dq conversion unit 112 converts, the current detected values (threephase currents) by the current sensors provided for each phase, into ad-axis current and a q-axis current which are components of anorthogonal two-dimensional rotation coordinate system with the fieldmagnet direction (direction of an axis of a magnetic field or fielddirection) as the d-axis.

A d-axis current feedback control unit 113 calculates a d-axis commandvoltage as an operation amount for feedback-controlling the d-axiscurrent to the d-axis current command value. Further, a q-axis currentfeedback control unit 114 calculates a q-axis command voltage as anoperation amount for feedback-controlling the q-axis current to theq-axis current command value. In each of these feedback control units113 and 114, the command voltage is calculated with the use of the PIfeedback method on the basis of the deviation with respect to thecurrent command values of the d-axis current and the q-axis current.

A three-phase conversion unit 115 converts the d-axis and q-axis commandvoltages into U-phase, V-phase, and W-phase command voltages. Moreover,each of the above units 111 to 115 is a feedback control unit thatperforms feedback control of the fundamental wave current according tothe dq conversion theory, and the U-phase, V-phase, and W-phase commandvoltages are feedback control values.

In addition, an operation signal generation unit 116 uses a well-knowntriangular wave carrier comparison method to generate an operationsignal of the first inverter 101 on the basis of the command voltages ofthe three phases. Specifically, the operation signal generation unit 116generates a switch operation signal (duty signal) of the upper and lowerarms in each phase by PWM control based on the magnitude comparisonbetween the signal obtained by standardizing the command voltage of thethree phases with the power supply voltage and the carrier signal suchas a triangular wave signal.

Further, the X, Y, and Z phase side also has the same configuration, anda dq conversion unit 122 converts the current detected values (threephase currents) by the current sensor provided for each phase into thed-axis current and q-axis current, which are components of an orthogonaltwo-dimensional rotation coordinate system with the field direction asthe d-axis.

A d-axis current feedback control unit 123 calculates a d-axis commandvoltage, and a q-axis current feedback control unit 124 calculates aq-axis command voltage. A three-phase conversion unit 125 converts thed-axis and q-axis command voltages into X-phase, Y-phase, and Z-phasecommand voltages. In addition, an operation signal generation unit 126generates an operation signal of the second inverter 102 on the basis ofthe command voltages of the three phases. Specifically, the operationsignal generation unit 126 generates a switch operation signal (dutysignal) of the upper and lower arms in each phase by PWM control basedon the magnitude comparison between the signal obtained by standardizingthe command voltage of the three phases with the power supply voltageand the carrier signal such as a triangular wave signal.

A driver 117 turns on/off the switches Sp and Sn of each of the threephases in the inverters 101 and 102 on the basis of the switch operationsignals generated by the operation signal generation units 116 and 126.

Subsequently, the torque feedback control processing will be described.This process is mainly used for the purpose of increasing the output ofthe rotating electric machine 10 and reducing the loss under operatingconditions in which the output voltage of each of the inverters 101 and102 becomes large, such as in a high rotation region and a high outputregion. The control device 110 selects and executes either the torquefeedback control processing or the current feedback control processingon the basis of the operating conditions of the rotating electricmachine 10.

FIG. 21 illustrates torque feedback control processing corresponding tothe U, V, and W phases and torque feedback control processingcorresponding to the X, Y, and Z phases. Moreover, in FIG. 21, the sameconfigurations as those in FIG. 20 are designated by the same referencesigns and the description thereof will be omitted. Here, first, thecontrol processing on the U, V, and W phase side will be described.

A voltage amplitude calculation unit 127 calculates a voltage amplitudecommand which is a command value of the magnitude of the voltage vector,on the basis of the power running torque command value or the powergeneration torque command value for the rotating electric machine 10 andthe electric angular velocity (o obtained by time-differentiating theelectrical angle θ.

A torque estimation unit 128 a calculates a torque estimated valuecorresponding to the U, V, and W phases on the basis of the d-axiscurrent and the q-axis current converted by the dq conversion unit 112.Moreover, the torque estimation unit 128 a may calculate the voltageamplitude command on the basis of the map information in which thed-axis current, the q-axis current, and the voltage amplitude commandare associated.

A torque feedback control unit 129 a calculates a voltage phase commandwhich is a command value of the phase of the voltage vector, as anoperation amount for feedback-controlling the torque estimated value tothe power running torque command value or the power generation torquecommand value. The torque feedback control unit 129 a calculates thevoltage phase command with the use of the PI feedback method on thebasis of the deviation of the torque estimated value with respect to thepower running torque command value or the power generation torquecommand value.

The operation signal generation unit 130 a generates an operation signalof the first inverter 101 on the basis of the voltage amplitude command,the voltage phase command, and the electrical angle θ. Specifically, theoperation signal generation unit 130 a calculates command voltages ofthree phases on the basis of the voltage amplitude command, the voltagephase command, and the electrical angle θ, and generates the switchoperation signal of the upper and lower arms in each phase by PWMcontrol based on the magnitude comparison between the signal obtained bystandardizing the calculated command voltages of three phases with thepower supply voltage and the carrier signal such as a triangular wavesignal.

By the way, the operation signal generation unit 130 a may generate theswitch operation signal on the basis of the pulse pattern informationwhich is map information in which the voltage amplitude command, thevoltage phase command, the electrical angle θ, and the switch operationsignal are associated, the voltage amplitude command, the voltage phasecommand, and the electrical angle θ.

Further, the X, Y, and Z phase side also has the same configuration, andthe torque estimation unit 128 b calculates a torque estimated valuecorresponding to the X, Y, and Z phases on the basis of the d-axiscurrent and the q-axis current converted by the dq conversion unit 122.

The torque feedback control unit 129 b calculates a voltage phasecommand as an operation amount for feedback-controlling the torqueestimated value to the power running torque command value or the powergeneration torque command value. The torque feedback control unit 129 bcalculates the voltage phase command with the use of the PI feedbackmethod on the basis of the deviation of the torque estimated value withrespect to the power running torque command value or the powergeneration torque command value.

The operation signal generation unit 130 b generates an operation signalof the first inverter 102 on the basis of the voltage amplitude command,the voltage phase command, and the electrical angle θ. Specifically, theoperation signal generation unit 130 b calculates command voltages ofthree phases on the basis of the voltage amplitude command, the voltagephase command, and the electrical angle θ, and generates the switchoperation signal of the upper and lower arms in each phase by PWMcontrol based on the magnitude comparison between the signal obtained bystandardizing the calculated command voltages of three phases with thepower supply voltage and the carrier signal such as a triangular wavesignal. The driver 117 turns on/off the switches Sp and Sn of each ofthe three phases in the inverters 101 and 102 on the basis of the switchoperation signals generated by the operation signal generation units 130a and 130 b.

Incidentally, the operation signal generation unit 130 b may generateswitch operation signals on the basis of the pulse pattern informationwhich is map information in which the voltage amplitude command, thevoltage phase command, the electrical angle θ, and the switch operationsignal are associated, the voltage amplitude command, the voltage phasecommand, and the electrical angle θ.

By the way, in the rotating electric machine 10, there is a concern thatelectrolytic corrosion of the bearings 21 and 22 may occur due to thegeneration of a shaft current. For example, there is a concern that,when the energization of the stator winding 51 is switched by switching,magnetic flux distortion occurs due to a slight deviation in switchingtiming (switching imbalance), which causes electrolytic corrosion in thebearings 21 and 22 that support the rotating shaft 11. The distortion ofthe magnetic flux occurs in accordance with the inductance of the stator50, and the electromotive voltage in the axial direction generated bythe distortion of the magnetic flux causes dielectric breakdown in thebearings 21 and 22, and electrolytic corrosion proceeds.

In this regard, in the present embodiment, the following threecountermeasures are taken as countermeasures against electrolyticcorrosion. A first electrolytic corrosion countermeasure is anelectrolytic corrosion suppression countermeasure by reducing theinductance due to the coreless stator 50 and by smoothing the magnetmagnetic flux of the magnet unit 42. A second electrolytic corrosioncountermeasure is an electrolytic corrosion suppression countermeasureby adopting a cantilever structure with the bearings 21 and 22 for therotating shaft. A third electrolytic corrosion countermeasure is anelectrolytic corrosion suppression countermeasure by molding the annularstator winding 51 together with the stator core 52 with a moldingmaterial. The details of each of these countermeasures will be describedbelow individually.

First, in the first electrolytic corrosion countermeasure, in the stator50, the spaces between each conductor group 81 in the circumferentialdirection are made teethless, and a sealing member 57 made of anon-magnetic material instead of the teeth (iron core) is providedbetween each conductor group 81 (see FIG. 10). This makes it possible toreduce the inductance of the stator 50. By reducing the inductance ofthe stator 50, even if the switching timing shift occurs when the statorwinding 51 is energized, the occurrence of magnetic flux distortion dueto the switching timing shift can be suppressed, and thus it is possibleto suppress the electrolytic corrosion of the bearings 21 and 22.Moreover, it is preferable that the inductance of the d-axis is equal toor less than the inductance of the q-axis.

Further, the magnets 91 and 92 are oriented in such a manner that thedirection of the axis of easy magnetization is more parallel to thed-axis on the d-axis side as compared with the q-axis side (see FIG. 9).As a result, the magnet magnetic flux on the d-axis is strengthened, andthe change in surface magnetic flux (increase/decrease in magnetic flux)from the q-axis to the d-axis becomes gentle at each magnetic pole.Therefore, the sudden voltage change caused by the switching imbalanceis suppressed, and thus a configuration that can contribute to thesuppression of electrolytic corrosion is implemented.

In the second electrolytic corrosion countermeasure, in the rotatingelectric machine 10, the respective bearings 21 and 22 are arrangedunevenly on either side in the axial direction with respect to the axialcenter of the rotor 40 (see FIG. 2). As a result, the influence ofelectrolytic corrosion can be reduced as compared with a configurationin which a plurality of bearings are provided on both sides of the rotorin the axial direction. That is, in a configuration in which the rotoris supported from both sides by a plurality of bearings, a closedcircuit that passes through the rotor, the stator, and each bearing(that is, each bearing on both sides in the axial direction with therotor therebetween) is formed as a high frequency magnetic flux isgenerated, and there is a concern about electrolytic corrosion of thebearing due to the shaft current. On the other hand, in theconfiguration in which the rotor 40 is cantilevered and supported by aplurality of bearings 21 and 22, the closed circuit is not formed andthe electrolytic corrosion of the bearings is suppressed.

Further, the rotating electric machine 10 has the followingconfiguration in connection with the configuration for arranging thebearings 21 and 22 on one side. In the magnet holder 41, the contactavoiding section that extends in the axial direction and avoids contactwith the stator 50 is provided at the intermediate section 45 thatprojects in the radial direction of the rotor 40 (see FIG. 2). In thiscase, when a closed circuit of the shaft current is formed via themagnet holder 41, the closed circuit length can be lengthened toincrease the circuit resistance. As a result, the electrolytic corrosionof the bearings 21 and 22 can be suppressed.

The holding member 23 of the bearing unit 20 is fixed to the housing 30on one side in the axial direction with the rotor 40 therebetween, andthe housing 30 and the unit base 61 (stator holder) are coupled to eachother on the other side (see FIG. 2). According to this configuration,it is possible to preferably implement a configuration in which therespective bearings 21 and 22 are unevenly arranged on one side of therotating shaft 11 in the axial direction. In addition, in thisconfiguration, since the unit base 61 is connected to the rotating shaft11 via the housing 30, the unit base 61 can be arranged at a positionelectrically separated from the rotating shaft 11. Moreover, if aninsulating member such as resin is interposed between the unit base 61and the housing 30, the unit base 61 and the rotating shaft 11 areelectrically further separated from each other. As a result, theelectrolytic corrosion of the bearings 21 and 22 can be appropriatelysuppressed.

In the rotating electric machine 10 of the present embodiment, the shaftvoltage acting on the bearings 21 and 22 is reduced by arranging therespective bearings 21 and 22 on one side, and the like. Further, thepotential difference between the rotor 40 and the stator 50 is reduced.Therefore, it is possible to reduce the potential difference acting onthe bearings 21 and 22 without using conductive grease in the bearings21 and 22. Since the conductive grease generally contains fine particlessuch as carbon, it is considered that noise is generated. In thisregard, in the present embodiment, non-conductive grease is used in thebearings 21 and 22. Therefore, it is possible to suppress theinconvenience of noise in the bearings 21 and 22. For example, in theapplication to an electric vehicle such as an electric vehicle, it isconsidered that a countermeasure against the noise of the rotatingelectric machine 10 is required, and it is possible to preferablyimplement the countermeasure against the noise.

In the third electrolytic corrosion countermeasure, the stator winding51 is molded together with the stator core 52 with a molding material tosuppress the displacement of the stator winding 51 in the stator 50 (seeFIG. 11). In particular, since the rotating electric machine 10 of thepresent embodiment does not have an interconductor member (teeth)between each conductor group 81 in the circumferential direction of thestator winding 51, there is a concern that the stator winding 51 may bedisplaced, but by molding the stator winding 51 together with the statorcore 52, the displacement of the conductor position of the statorwinding 51 is suppressed. Consequently, it is possible to suppress thedistortion of the magnetic flux due to the displacement of the statorwinding 51 and the occurrence of electrolytic corrosion of the bearings21 and 22 due to the distortion.

Moreover, since the unit base 61 as a housing member that fixes thestator core 52 is made of carbon fiber reinforced plastic (CFRP), theelectric discharge to the unit base 61 is suppressed as compared withthe case where it is made of, for example, aluminum. Thus, a suitablecountermeasure against electrolytic corrosion is possible.

In addition to that, as a countermeasure against electrolytic corrosionof the bearings 21 and 22, it is also possible to use a configuration inwhich at least one of the outer ring 25 and the inner ring 26 is made ofa ceramic material, or in which an insulating sleeve is provided on theoutside of the outer ring 25.

Hereinafter, other embodiments will be described with a focus ondifferences from the first embodiment.

Second Embodiment

In the present embodiment, the polar anisotropic structure of the magnetunit 42 in the rotor 40 is changed, which will be described in detailbelow.

As illustrated in FIGS. 22 and 23, the magnet unit 42 is composed withthe use of a magnet array called a Halbach array. That is, the magnetunit 42 has a first magnet 131 in which the magnetization direction(direction of the magnetization vector) is the radial direction and asecond magnet 132 in which the magnetization direction (direction of themagnetization vector) is the circumferential direction. The firstmagnets 131 are arranged at predetermined intervals in thecircumferential direction, and the second magnets 132 are arranged at aposition between the adjacent first magnets 131 in the circumferentialdirection. The first magnet 131 and the second magnet 132 are permanentmagnets made of rare earth magnets such as neodymium magnets.

The first magnets 131 are arranged so as to be apart from each other inthe circumferential direction in such a manner that the poles on theside facing the stator 50 (inside in the radial direction) arealternately N poles and S poles. Further, the second magnets 132 arearranged next to each first magnet 131 in such a manner that thepolarities alternate in the circumferential direction. The cylindricalsection 43 provided so as to surround each of the magnets 131 and 132 ispreferably a soft magnetic substance core made of a soft magneticmaterial, and functions as a back core. Moreover, the magnet unit 42 ofthe second embodiment also has the same relation of the axis of easymagnetization with respect to the d-axis and the q-axis in the d-qcoordinate system as in the first embodiment.

Further, a magnetic substance 133 made of a soft magnetic substance isarranged on radially outside the first magnet 131, that is, on the sideof the cylindrical section 43 of the magnet holder 41. For example, themagnetic substance 133 is preferably made of an electromagnetic steelsheet, soft iron, or a dust core material. In this case, thecircumferential length of the magnetic substance 133 is the same as thecircumferential length of the first magnet 131 (particularly, thecircumferential length of the outer peripheral portion of the firstmagnet 131). Further, in a state where the first magnet 131 and themagnetic substance 133 are integrated, the radial thickness of theintegrated object is the same as the radial thickness of the secondmagnet 132. In other words, the radial thickness of the first magnet 131is thinner than that of the second magnet 132 by the amount of themagnetic substance 133. Each of the magnets 131 and 132 and the magneticsubstance 133 are fixed to each other by, for example, an adhesive. Inthe magnet unit 42, the radial outside of the first magnet 131 is theopposite side to the stator 50, and the magnetic substance 133 isprovided on the side opposite to the stator 50 (opposite-to-stator side)in both sides of the first magnet 131 in the radial direction.

A key 134 is formed on the outer peripheral portion of the magneticsubstance 133 as a protrusion that protrudes outward in the radialdirection, that is, toward the side of the cylindrical section 43 of themagnet holder 41. Further, a key groove 135 is formed on the innerperipheral surface of the cylindrical section 43 as a recess for housingthe key 134 of the magnetic substance 133. The protruding shape of thekey 134 and the groove shape of the key groove 135 are the same, and thesame number of key grooves 135 as the key 134 are formed correspondingto the key 134 formed on each magnetic substance 133. By engaging thekey 134 and the key groove 135, the displacement of the first magnet 131and the second magnet 132 and the magnet holder 41 in thecircumferential direction (rotation direction) is suppressed. Moreover,it is optional whether the key 134 and the key groove 135 (protrusionand recess) are provided in either of the cylindrical section 43 or themagnetic substance 133 of the magnet holder 41, and contrary to theabove, it is also possible to provide the key groove 135 on the outerperipheral portion of the magnetic substance 133 and to provide the key134 on the inner peripheral portion of the cylindrical section 43 of themagnet holder 41.

Here, in the magnet unit 42, the magnetic flux density in the firstmagnet 131 can be increased by alternately arranging the first magnet131 and the second magnet 132. Therefore, in the magnet unit 42, themagnetic flux can be concentrated on one side, and the magnetic flux canbe strengthened on the side closer to the stator 50.

Further, by arranging the magnetic substance 133 radially outside thefirst magnet 131, that is, on the opposite-to-stator side, it ispossible to suppress partial magnetic saturation on the radial outsideof the first magnet 131, and thus demagnetization of the first magnet131 caused by the magnetic saturation can be suppressed. As a result, itis accordingly possible to increase the magnetic force of the magnetunit 42. The magnet unit 42 of the present embodiment has, so to speak,a configuration in which a portion of the first magnet 131 in whichdemagnetization is likely to occur is replaced with the magneticsubstance 133.

FIGS. 24A and 24B are diagrams specifically illustrating the flow ofmagnetic flux in the magnet unit 42, FIG. 24A illustrates a case where aconventional configuration is used in which the magnet unit 42 does nothave the magnetic substance 133, and FIG. 24B illustrates a case wherethe configuration of the present embodiment having the magneticsubstance 133 in the magnet unit 42 is used. Moreover, in FIGS. 24A and24B, the cylindrical section 43 of the magnet holder 41 and the magnetunit 42 are illustrated in a linearly developed manner, with the lowerside of the figure being the stator side and the upper side being theopposite-to-stator side.

In the configuration of FIG. 24A, the magnetic flux acting surface ofthe first magnet 131 and the side surface of the second magnet 132 arein contact with the inner peripheral surface of the cylindrical section43, respectively. Further, the magnetic flux acting surface of thesecond magnet 132 is in contact with the side surface of the firstmagnet 131. In this case, in the cylindrical section 43, the combinedmagnetic flux of a magnetic flux F1 that enters the contact surface withthe first magnet 131 through the outer path of the second magnet 132 andthe magnetic flux that is substantially parallel to the cylindricalsection 43 and attracts a magnetic flux F2 of the second magnet 132 isgenerated. Therefore, there is a concern that magnetic saturation maypartially occur in the vicinity of the contact surface between the firstmagnet 131 and the second magnet 132 in the cylindrical section 43.

On the other hand, in the configuration of FIG. 24B, the magneticsubstance 133 is formed between the magnetic flux acting surface of thefirst magnet 131 and the inner peripheral surface of the cylindricalsection 43 on the side opposite to the stator 50 of the first magnet131, and therefore the magnetic substance 133 allows the passage ofmagnetic flux. Consequently, magnetic saturation in the cylindricalsection 43 can be suppressed, and the proof stress againstdemagnetization is improved.

Further, in the configuration of FIG. 24B, unlike FIG. 24A, the flux F2that promotes magnetic saturation can be cancelled As a result, thepermeance of the entire magnetic circuit can be effectively improved.With such a configuration, the magnetic circuit characteristics can bemaintained even under severe high heat conditions.

Further, the magnet magnetic path passing through the inside of themagnet becomes longer than that of a radial magnet in a conventional SPMrotor. Therefore, the magnet permeance can rise, the magnetic force canbe enhanced, and the torque can be increased. Furthermore, the magneticflux is concentrated in the center of the d-axis, and thus the sine wavematching rate can be increased. In particular, if the current waveformis made into a sine wave or a trapezoidal wave by PWM control, or if aswitching IC energized at 120 degrees is used, the torque can beincreased more effectively.

Moreover, in a case where the stator core 52 is made of anelectromagnetic steel sheet, the radial thickness of the stator core 52is preferably ½ or more than ½ of the radial thickness of the magnetunit 42. For example, the radial thickness of the stator core 52 ispreferably ½ or more of the radial thickness of the first magnet 131provided at the center of the magnetic pole in the magnet unit 42.Further, the radial thickness of the stator core 52 is preferablysmaller than the radial thickness of the magnet unit 42. In this case,the magnet magnetic flux is approximately 1 [T], and the saturationmagnetic flux density of the stator core 52 is 2 [T]. Therefore, bysetting the radial thickness of the stator core 52 to ½ or more of theradial thickness of the magnet unit 42, it is possible to preventmagnetic flux leakage to the inner peripheral side of the stator core52.

In a magnet having a Halbach structure or a polar anisotropic structure,since the magnetic path has a pseudo arc shape, the magnetic flux can beincreased in proportion to the thickness of the magnet that handles themagnetic flux in the circumferential direction. In such a configuration,it is considered that the magnetic flux flowing through the stator core52 does not exceed the magnetic flux in the circumferential direction.That is, in a case where an iron-based metal having a saturationmagnetic flux density of 2 [T] is used with respect to a magnetic fluxof the magnet 1 [T], if the thickness of the stator core 52 is set tohalf or more of the magnet thickness, it is possible to provide arotating electric machine that is not magnetically saturated and issuitably small and lightweight. Here, since the diamagnetic field fromthe stator 50 acts on the magnet magnetic flux, the magnet magnetic fluxis generally 0.9 [T] or less. Therefore, if the stator core has half thethickness of the magnet, its magnetic permeability can be kept suitablyhigh.

Hereinafter, a modification in which a part of the above-describedconfiguration is modified will be described.

First Modification

In the above embodiment, the outer peripheral surface of the stator core52 has a curved surface without unevenness, and a plurality of conductorgroups 81 are arranged side by side at predetermined intervals on theouter peripheral surface, but this may be changed. For example, asillustrated in FIG. 25, the stator core 52 has an annular yoke 141provided on the side opposite to the rotor 40 (lower side in the figure)on both sides of the stator winding 51 in the radial direction andprotruding sections 142 extending from the yoke 141 so as to protrudebetween the straight sections 83 adjacent to each other in thecircumferential direction. The protruding sections 142 are provided atpredetermined intervals on the radially outside the yoke 141, that is,on the rotor 40 side. The respective conductor groups 81 of the statorwinding 51 are engaged with the protruding sections 142 in thecircumferential direction, and are arranged side by side in thecircumferential direction while using the protruding section 142 as apositioning section of the conductor group 81. Moreover, the protrudingsection 142 corresponds to the “interconductor member”.

In the protruding section 142, the radial thickness dimension from theyoke 141, in other words, as illustrated in FIG. 25, in the radialdirection of the yoke 141, a distance W from the inner side surface 320adjacent to the yoke 141 of the straight section 83 to the apex of theprotruding section 142 is smaller than ½ of the radial thicknessdimension of the straight section 83 radially adjacent to the yoke 141among the plurality of straight sections 38 inside and outside theradial direction (H1 in the figure). In other words, the non-magneticmember (sealing member 57) should occupy a range of three-quarters of adimension (thickness) T1 of the conductor group 81 (conducting member)in the radial direction of the stator winding 51 (stator core 52) (twicethe thickness of the conductor wire 82, in other words, the shortestdistance between the surface 320 in contact with the stator core 52 ofthe conductor group 81 and a surface 330 facing the rotor 40 of theconductor group 81). Due to the thickness limitation of the protrudingsection 142, the protruding section 142 does not function as teethbetween the conductor groups 81 (that is, the straight section 83)adjacent to each other in the circumferential direction, and themagnetic path is not formed by the teeth. Not all of the protrudingsections 142 may not be provided between the conductor groups 81arranged in the circumferential direction, but should be providedbetween at least one set of the conductor groups 81 adjacent to eachother in the circumferential direction. For example, the protrudingsections 142 are preferably provided at equal intervals for eachpredetermined number of the conductor groups 81 in the circumferentialdirection. The shape of the protruding section 142 may be any shape suchas a rectangular shape or an are shape.

Further, the straight section 83 may be provided as a single layer onthe outer peripheral surface of the stator core 52. Consequently, in abroad sense, the radial thickness dimension of the protruding section142 from the yoke 141 may be smaller than ½ of the radial thicknessdimension of the straight section 83.

Moreover, assuming a virtual circle centered on the shaft center of therotating shaft 11 and passing through the radial center position of thestraight section 83 radially adjacent to the yoke 141, the protrudingsection 142 preferably has a shape that protrudes from the yoke 141within the range of the virtual circle, in other words, a shape thatdoes not protrude radially outward of the virtual circle (that is, onthe rotor 40 side).

According to the above configuration, the protruding section 142 has alimited radial thickness dimension and does not function as the teethbetween the straight sections 83 adjacent to each other in thecircumferential direction. Therefore, it is possible to bring therespective adjacent straight sections 83 closer to each other ascompared with the case where the teeth are provided between therespective straight sections 83. As a result, the cross-sectional areaof the conductor 82 a can be increased, and the heat generated by theenergization of the stator winding 51 can be reduced. In such aconfiguration, the absence of teeth makes it possible to eliminatemagnetic saturation and increase the energization current to the statorwinding 51. In this case, it is possible to preferably cope with theincrease in the amount of heat generated as the energization currentincreases. Further, in the stator winding 51, since the turn section 84is shifted in the radial direction and has an interference avoidancesection for avoiding interference with other turn sections 84, thedifferent turn sections 84 can be separated from each other in theradial direction. As a result, heat dissipation can be improved even inthe turn section 84. As described above, it is possible to optimize theheat dissipation performance of the stator 50.

Further, if the yoke 141 of the stator core 52 and the magnet unit 42 ofthe rotor 40 (that is, the magnets 91 and 92) are separated by apredetermined distance or more, the radial thickness dimension of theprotruding section 142 is not limited to H1 in FIG. 25 Specifically, ifthe yoke 141 and the magnet unit 42 are separated by 2 mm or more, theradial thickness dimension of the protruding section 142 may be H1 ormore in FIG. 25. For example, in a case where the radial thicknessdimension of the straight section 83 exceeds 2 mm and the conductorgroup 81 is composed of two layers of conductor wires 82 inside andoutside the radial direction, the protruding section 142 may be providedin the straight section 83 not adjacent to the yoke 141, that is, in therange from the yoke 141 to the half position of the second conductorwire 82. In this case, if the radial thickness dimension of theprotruding section 142 is up to “H1×3/2”, the effect can be obtained nota little by increasing the conductor cross-sectional area in theconductor group 81.

Further, the stator core 52 may have the configuration illustrated inFIG. 26. Moreover, although the sealing member 57 is omitted in FIG. 26,the sealing member 57 may be provided. In FIG. 26, for convenience, themagnet unit 42 and the stator core 52 are illustrated in a linearlydeveloped manner.

In the configuration of FIG. 26, the stator 50 has the protrudingsection 142 as an interconductor member between the conductor wires 82(that is, the straight section 83) adjacent to each other in thecircumferential direction. When the stator winding 51 is energized, thestator 50 magnetically functions together with one of the magnetic poles(N pole or S pole) of the magnet unit 42, and has a part 350 extendingin the circumferential direction of the stator 50. When thecircumferential length of the stator 50 of this part 350 is Wn, thetotal width of the protruding sections 142 existing in this length rangeWn (that is, the total dimension of the stator 50 in the circumferentialdirection) is Wt, the saturation magnetic flux density of the protrudingsection 142 is Bs, the width dimension for one pole of the magnet unit42 in the circumferential direction is Wm, and the residual magneticflux density of the magnet unit 42 is Br, the protruding section 142 ismade of a magnetic material of a formula (1).

Wt*Bs≤Wm*Br  (1)

Moreover, the range Wn is set so as to include a plurality of conductorgroups 81 adjacent to each other in the circumferential direction andinclude a plurality of conductor groups 81 having overlapping excitationtimes. In doing so, it is preferable to set the center of the void 56 ofthe conductor group 81 as a reference (boundary) when setting the rangeWn. For example, in the case of the configuration illustrated in FIG.26, the conductor groups 81 up to the fourth in order from the one withthe shortest distance from the center of the magnetic pole of the N polein the circumferential direction correspond to the aforementionedplurality of conductor groups 81. In addition, the range Wn is set so asto include the four conductor groups 81. In doing so, the ends (startingpoint and ending point) of the range Wn are set as the center of thevoid 56.

In FIG. 26, since halves of the protruding sections 142 are included atboth ends of the range Wn, the range Wn includes a total of fourprotruding sections 142. Consequently, when the width of the protrudingsection 142 (that is, the dimension of the protruding section 142 in thecircumferential direction of the stator 50, in other words, the intervalbetween the adjacent conductor groups 81) is A, the total width of theprotruding sections 142 included in the range Wn is Wt=½A+A+A+A+½A=4A.

Specifically, in the present embodiment, the three-phase winding of thestator winding 51 is a distributed winding, and in the stator winding51, the number of protruding sections 142 with respect to one pole ofthe magnet unit 42, that is, the number of voids 56 between therespective conductor groups 81 is a “number of phases*Q”. Here, Q is thenumber of the one-phase conductor wires 82 that are in contact with thestator core 52. Moreover, in a case where the conductor wires 82 are theconductor group 81 stacked in the radial direction of the rotor 40, itcan also be considered to be the number of the conductor wires 82 on theinner peripheral side of the one-phase conductor group 81. In this case,when the three-phase winding of the stator winding 51 is energized in apredetermined order for each phase, the protruding sections 142 for twophases are excited in one pole. Consequently, the total circumferentialwidth dimension Wt of the protruding section 142 excited by theenergization of the stator winding 51 in the range for one pole of themagnet unit 42 is “the number of excited phases*Q*A=2*2*A” when thecircumferential width dimension of the protruding section 142 (that is,the void 56) is A.

In addition, after the total width dimension Wt is defined in this way,in the stator core 52, the protruding section 142 is configured as amagnetic material fulfilling the relation (1) above. Moreover, the totalwidth dimension Wt is also the circumferential dimension of the portionwhere the relative magnetic permeability can be larger than 1 in onepole. Further, in consideration of a margin, the total width dimensionWt may be set as the circumferential width dimension of the protrudingsection 142 in one magnetic pole. Specifically, since the number ofprotruding sections 142 with respect to one pole of the magnet unit 42is “number of phases*Q”, the circumferential width dimension (totalwidth dimension Wt) of the protruding sections 142 in one magnetic polemay be set to “the number of phases*Q*A=3*2*A=6A”.

Moreover, the distributed winding referred to here is a one-pole pairperiod (N-pole and S-pole) of the magnetic pole, and has a one-pole pairof the stator winding 51. The one-pole pair of the stator winding 51referred to here is composed of two straight sections 83 and a turnsection 84 in which currents flow in opposite directions and which areelectrically connected at the turn section 84. If the above conditionsare met, even a Short Pitch Winding is regarded as an equivalent of adistributed winding of a Full Pitch Winding.

Next, an example in the case of concentrated winding is indicated. Theconcentrated winding referred to here is that the width of the one-polepair of magnetic poles and the width of the one-pole pair of the statorwinding 51 are different. Example of concentrated winding include aconcentrated winding that has relation such as three conductor groups 81for one magnetic pole pair, three conductor groups 81 for two magneticpole pairs, nine conductor groups 81 for four magnetic pole pairs, andnine conductor groups 81 for five magnetic pole pairs.

Here, in a case where the stator winding 51 is a concentrated winding,when the three-phase windings of the stator winding 51 are energized ina predetermined order, the stator windings 51 for two phases areexcited. As a result, the protruding sections 142 for two phases areexcited. Consequently, the circumferential width dimension Wt of theprotruding section 142 excited by the energization of the stator winding51 in the range for one pole of the magnet unit 42 is “A*2”. Inaddition, after the total width dimension Wt is defined in this way, theprotruding section 142 is configured as a magnetic material fulfillingthe relation (1) above. Moreover, in the case of the concentratedwinding indicated above, the total circumferential width of theprotruding sections 142 of the stator 50 in the region surrounded by theconductor groups 81 of the same phase is defined as A. Further, Wm inthe concentrated winding corresponds to “the entire circumference of thesurface facing the air gap of the magnet unit 42” *“the number ofphases”/“the number of dispersions of the conductor group 81”.

Incidentally, for magnets with a BH product of 20 [MGOe (kJ/m{circumflexover ( )}3)] or more, such as neodymium magnets, samarium-cobaltmagnets, and ferrite magnets, Bd=over 1.0 [T], and for iron, Br=over 2.0[T]. Therefore, as the high output motor, in the stator core 52, theprotruding section 142 may be a magnetic material fulfilling therelation of Wt<½ *Wm.

Further, in a case where the conductor wire 82 includes an outer layercoating 182 as described below, the conductor wire 82 may be arranged inthe circumferential direction of the stator core 52 in such a mannerthat the outer layer coatings 182 of the conductor wires 82 come intocontact with each other. In this case, Wt can be regarded as 0 or thethickness of the outer layer coating 182 of both conductor wires 82 incontact with each other.

In the configurations of FIGS. 25 and 26, an interconductor member(protruding section 142) that is disproportionately small with respectto the magnet magnetic flux on the rotor 40 side is provided. Moreover,the rotor 40 is a flat surface magnet type rotor having a low inductanceand does not have saliency in terms of magnetic resistance. In such aconfiguration, the inductance of the stator 50 can be reduced, thegeneration of magnetic flux distortion due to the deviation of theswitching timing of the stator winding 51 is suppressed, and thus theelectrolytic corrosion of the bearings 21 and 22 is suppressed.

Second Modification

The following configuration can also be adopted as the stator 50 usingthe interconductor member fulfilling the relation of the above formula(1). In FIG. 27, a tooth-shaped section 143 is provided as aninterconductor member on the outer peripheral surface side of the statorcore 52 (upper surface side in the figure). The tooth-shaped section 143is provided at predetermined intervals in the circumferential directionso as to protrude from the yoke 141, and have the same thicknessdimension as that of the conductor group 81 in the radial direction. Theside surface of the tooth-shaped section 143 is in contact with eachconductor wire 82 of the conductor group 81. However, there may be a gapbetween the tooth-shaped section 143 and each conductor wire 82.

The tooth-shaped section 143 is provided with a limitation on the widthdimension in the circumferential direction, and is provided with polarteeth (stator teeth) that are disproportionately thin with respect tothe amount of magnets. With such a configuration, the tooth-shapedsection 143 is surely saturated by the magnetic flux of the magnet at1.8 T or more, and the inductance can be lowered by lowering thepermeance.

Here, in the magnet unit 42, when the surface area per pole of themagnetic flux acting surface on the stator side is Sm and the residualmagnetic flux density of the magnet unit 42 is Br, the magnetic flux onthe magnet unit side is, for example, “Sm*Br”. Further, when the surfacearea on the rotor side in each tooth-shaped section 143 is St, thenumber per phase of the conductor wire 82 is m, and the tooth-shapedsections 143 for two phases are excited in one pole by energization ofthe stator winding 51, the magnetic flux on the stator side is, forexample, “St*m*2*Bs”. In this case, the inductance is reduced bylimiting the dimension of the tooth-shaped section 143 in such a mannerthat a relation (2) is established.

St*m*2*Bs<Sm*Br  (2)

Moreover, in a case where the magnet unit 42 and the tooth-shapedsection 143 have the same axial dimension, when the circumferentialwidth dimension for one pole of the magnet unit 42 is Wm, and thecircumferential width dimension of the tooth-shaped section 143 is Wst,then the above formula (2) is replaced as in a formula (3).

Wst*m*2*Bs<Wm*Br  (3)

More specifically, assuming that, for example, Bs=2T, Br=1T, and m=2,the above formula (3) has a relation of “Wst<Wm/8”. In this case, theinductance is reduced by making the width dimension Wst of thetooth-shaped section 143 smaller than ⅛ of the width dimension Wm forone pole of the magnet unit 42. Moreover, if the number m is 1, thewidth dimension Wst of the tooth-shaped section 143 is preferably madeto be smaller than ¼ of the width dimension Wm for one pole of themagnet unit 42.

Moreover, in the above formula (3), “Wst*m*2” corresponds to thecircumferential width dimension of the tooth-shaped section 143 excitedby energization of the stator winding 51 in the range for one pole ofthe magnet unit 42.

In the configuration of FIG. 27, similarly to the configurations ofFIGS. 25 and 26 described above, the interconductor member (tooth-shapedsection 143) which is disproportionately small with respect to themagnet magnetic flux on the rotor 40 side is provided. In such aconfiguration, the inductance of the stator 50 can be reduced, thegeneration of magnetic flux distortion due to the deviation of theswitching timing of the stator winding 51 is suppressed, and thus theelectrolytic corrosion of the bearings 21 and 22 is suppressed.

Third Modification

In the above embodiment, the sealing member 57 covering the statorwinding 51 is provided radially outside the stator core 52 in the rangeincluding all the conductor groups 81, that is, in the range in whichthe radial thickness dimension is larger than the radial thicknessdimension of each conductor group 81, but this may be changed. Forexample, as illustrated in FIG. 28, the sealing member 57 is provided insuch a manner that a part of the conductor wire 82 protrudes. Morespecifically, the sealing member 57 is provided in a state where a partof the conductor wire 82 which is the outermost in the radial directionin the conductor group 81 is exposed on the radial outside, that is, onthe stator 50 side. In this case, the radial thickness dimension of thesealing member 57 may be the same as or smaller than the radialthickness dimension of each conductor group 81.

Fourth Modification

As illustrated in FIG. 29, in the stator 50, each conductor group 81 maynot be sealed by the sealing member 57. That is, the sealing member 57that covers the stator winding 51 is not used. In this case, nointerconductor member is provided between the conductor groups 81arranged in the circumferential direction, and an airspace is formed. Inshort, the interconductor member is not provided between the conductorgroups 81 arranged in the circumferential direction. Moreover, air maybe regarded as a non-magnetic substance or an equivalent of anon-magnetic substance as Bs=0, and air may be arranged in thisairspace.

Fifth Modification

In a case where the interconductor member in the stator 50 is made of anon-magnetic material, it is possible to use a material other than resinas the non-magnetic material. For example, a metal-based non-magneticmaterial may be used, such as using SUS304 which is an austeniticstainless steel.

Sixth Modification

The stator 50 may be configured not to include the stator core 52. Inthis case, the stator 50 is composed of the stator winding 51illustrated in FIG. 12. Moreover, in the stator 50 that does not includethe stator core 52, the stator winding 51 may be sealed with a sealingmaterial. Alternatively, the stator 50 may be configured to include anannular winding holding section made of a non-magnetic material such assynthetic resin as an alternative to the stator core 52 made of a softmagnetic material.

Seventh Modification

In the above first embodiment, the plurality of magnets 91 and 92arranged in the circumferential direction are used as the magnet unit 42of the rotor 40, but this may be changed, and an annular magnet which isan annular permanent magnet may be used as the magnet unit 42.Specifically, as illustrated in FIG. 30, an annular magnet 95 is fixedradially inside the cylindrical section 43 of the magnet holder 41. Theannular magnet 95 is provided with a plurality of magnetic poles havingalternating polarities in the circumferential direction, and the magnetis integrally formed on both the d-axis and the q-axis. The annularmagnet 95 is formed with an arc shaped magnet magnetic path such thatthe direction of orientation is the radial direction on the d-axis ofeach magnetic pole and the direction of orientation is thecircumferential direction on the q-axis between the respective magneticpoles.

Moreover, in the annular magnet 95, the orientation should be made insuch a manner that an arc-shaped magnet magnetic path is formed, inwhich the axis of easy magnetization is parallel to the d-axis or closeto parallel to the d-axis in the portion near the d-axis, and the axisof easy magnetization is orthogonal to the q-axis or close to parallelto the q-axis in the portion near the q-axis.

Eighth Modification

In this modification, a part of the control method of the control device110 is changed. In this modification, the difference from theconfiguration described in the first embodiment will be mainlydescribed.

First, with reference to FIG. 31, the processing in the operation signalgeneration units 116 and 126 illustrated in FIG. 20 and the operationsignal generation units 130 a and 130 b illustrated in FIG. 21 will bedescribed. Moreover, the processing in each operation signal generationunit 116, 126, 130 a, and 130 b is basically the same. Therefore, in thefollowing, the processing of the operation signal generation unit 116will be described as an example.

The operation signal generation unit 116 includes a carrier generationunit 116 a and U, V, W phase comparators 116 bU, 116 bV, and 116 bW. Inthe present embodiment, the carrier generation unit 116 a generates andoutputs a triangular wave signal as a carrier signal SigC.

The carrier signal SigC generated by the carrier generation unit 116 aand the U, V, W phase command voltages calculated by the three-phaseconversion unit 115 are input to the U, V, W phase comparators 116 bU,116 bV, and 116 bW. The U, V, W phase command voltages are, for example,sinusoidal waveforms, and the phases are shifted by 120° depending onthe electrical angle.

The U, V, W phase comparators 116 bU, 116 bV, and 116 bW generate theoperation signals of the respective switches Sp and Sn of the upper armand the lower arm of the U, V, W phases in the first inverter 101, byPWM (pulse width modulation) control based on the magnitude comparisonbetween the U, V, W phase command voltages and the carrier signal SigC.Specifically, the operation signal generation unit 116 generates theoperation signals of the respective switches Sp and Sn of the U, V, Wphases by PWM control based on the magnitude comparison between thesignal obtained by standardizing the U, V. W command voltages with thepower supply voltage and the carrier signal. The driver 117 turns on/offeach of the switches Sp and Sn of the U, V, W phases in the inverter 101on the basis of the operation signals generated by the operation signalgeneration unit 116.

The control device 110 performs processing that changes the carrierfrequency fc of the carrier signal SignC, that is, the switchingfrequency of each of the switches Sp and Sn. The carrier frequency fc isset high in the low torque region or high rotation region of therotating electric machine 10 and low in the high torque region of therotating electric machine 10. This setting is made in order to suppressa decrease in controllability of the current flowing through each phasewinding.

That is, as the stator 50 becomes coreless, the inductance of the stator50 can be reduced. Here, when the inductance becomes low, the electricaltime constant of the rotating electric machine 10 becomes small. As aresult, there is a concern that the ripple of the current flowingthrough each phase winding increases, the controllability of the currentflowing through the winding decreases, and the current control diverges.The effect of this decrease in controllability can be more pronouncedwhen the current flowing through the winding (for example, the effectivevalue of the current) is included in the low current region than in thehigh current region. In order to deal with this problem, in thismodification, the control device 110 changes the carrier frequency fc.

The processing that changes the carrier frequency fc will be describedwith reference to FIG. 32. This processing is repeatedly executed by thecontrol device 110, for example, at a predetermined control cycle as theprocessing of the operation signal generation unit 116.

In step S10, it is determined whether the current flowing through awinding 51 a of each phase is in the low current region. This processingis processing for determining that the current torque of the rotatingelectric machine 10 is in the low torque region. Examples of the methodfor determining whether the current is included in the low currentregion include the following first and second methods.

<First Method>

The torque estimated value of the rotating electric machine 10 iscalculated on the basis of the d-axis current and the q-axis currentconverted by the dq conversion unit 112. Then, when it is determinedthat the calculated torque estimated value is less than the torquethreshold value, it is determined that the current flowing through thewinding 51 a is included in the low current region, and when it isdetermined that the torque estimated value is equal to or more than thetorque threshold value, it is determined that the current flowingthrough the winding 51 a is included in the high current region. Here,the torque threshold value should be set to, for example, ½ of thestarting torque (also referred to as restraint torque) of the rotatingelectric machine 10.

<Second Method>

When it is determined that the rotation angle of the rotor 40 detectedby the angle detector is equal to or greater than a speed thresholdvalue, it is determined that the current flowing through the winding 51a is included in the low current region, that is, in the high rotationregion. Here, the speed threshold value should be set to, for example,the rotation speed when the maximum torque of the rotating electricmachine 10 becomes the torque threshold value.

If a negative determination is made in step S10, it is determined to bea high current region, and the processing proceeds to step S11. In stepS11, the carrier frequency fc is set to a first frequency fL.

If an affirmative determination is made in step S10, the processingproceeds to step S12, and the carrier frequency fc is set to a secondfrequency fH which is higher than the first frequency fL.

According to this modification described above, the carrier frequency fcis set higher when the current flowing through each phase winding isincluded in the low current region than when it is included in the highcurrent region. Therefore, in the low current region, the switchingfrequencies of the switches Sp and Sn can be increased, and the increasein current ripple can be suppressed. As a result, it is possible tosuppress a decrease in current controllability.

On the other hand, when the current flowing through each phase windingis included in the high current region, the carrier frequency fc is setlower than when it is included in the low current region. In the highcurrent region, the amplitude of the current flowing through the windingis larger than in the low current region, and therefore the increase incurrent ripple due to the low inductance has a small effect on thecurrent controllability. Therefore, in the high current region, thecarrier frequency fc can be set lower than in the low current region,and the switching loss of the respective inverters 101 and 102 can bereduced.

In this modification, the following embodiments can be implemented.

-   -   In a case where the carrier frequency fc is set to the first        frequency fL, when an affirmative determination is made in step        S10 of FIG. 32, the carrier frequency fc may be gradually        changed from the first frequency fL to the second frequency fH.

Further, in a case where the carrier frequency fc is set to the secondfrequency fH, when a negative determination is made in step S10, thecarrier frequency fc may be gradually changed from the second frequencyfH to the first frequency fL.

-   -   A switch operation signal may be generated by space vector        modulation (SVM) control instead of PWM control. Even in this        case, the above-mentioned change in switching frequency can be        applied.

Ninth Modification

In each of the above embodiments, two pairs of conductors of each phaseconstituting the conductor group 81 are connected in parallel asillustrated in FIG. 33A. FIG. 33A is a diagram illustrating theelectrical connection of first and second conductors 88 a and 88 b,which are two pairs of conductors. Here, as an alternative to theconfiguration illustrated in FIG. 33A, as illustrated in FIG. 33B, thefirst and second conductors 88 a and 88 b may be connected in series.

Further, three or more pairs of multilayer conductors may be laminatedand arranged in the radial direction. FIG. 34 illustrates aconfiguration in which first to fourth conductors 88 a to 88 d, whichare four pairs of conductors, are laminated and arranged. The first tofourth conductors 88 a to 88 d are arranged in the radial direction inthe order of the first, second, third, and fourth conductors 88 a, 88 b,88 c, and 88 d from the side closer to the stator core 52.

Here, as illustrated in FIG. 33C, the third and fourth conductors 88 cand 88 d are connected in parallel, the first conductor 88 a may beconnected to one end of the parallel connection body, and the secondconductor 88 b may be connected to the other end. When connected inparallel, the current density of the conductors connected in parallelcan be reduced, and heat generation during energization can besuppressed. Therefore, in the configuration in which the tubular statorwinding is assembled to the housing (unit base 61) in which the coolingwater passage 74 is formed, the first and second conductors 88 a and 88b that are not connected in parallel are arranged on the stator core 52side that abuts on the unit base 61, and the third and fourth conductors88 c and 88 d that are connected in parallel are arranged on theopposite-to-stator core side. As a result, the cooling performance ofeach of the conductors 88 a to 88 d in the multilayer conductorstructure can be equalized.

Moreover, the radial thickness dimension of the conductor group 81composed of the first to fourth conductors 88 a to 88 d should besmaller than the circumferential width dimension for one phase in onemagnetic pole.

Tenth Modification

The rotating electric machine 10 may have an inner rotor structure(adduction structure).

In this case, for example, in the housing 30, it is preferable that thestator 50 is provided on the radially outside and the rotor 40 isprovided on the radially inside. Further, it is preferable that theinverter unit 60 is provided on one side or both sides of both ends ofthe stator 50 and the rotor 40 in the axial direction. FIG. 35 is across-sectional view of the rotor 40 and the stator 50, and FIG. 36 is aview illustrating a part of the rotor 40 and the stator 50 illustratedin FIG. 35 in an enlarged manner.

The configurations of FIGS. 35 and 36, which are premised on an innerrotor structure, have the same configurations as those of FIGS. 8 and 9except that the rotor 40 and stator 50 are reversed in and out of theradial direction. Briefly, the stator 50 has a stator winding 51 havinga flat conductor structure and a stator core 52 having no teeth. Thestator winding 51 is assembled radially inside the stator core 52. Thestator core 52 has one of the following configurations, as in the caseof the outer rotor structure.

A In the stator 50, an interconductor member is provided between eachconductor section in the circumferential direction, and as theinterconductor member, a magnetic material having a relation ofWt*Bs≤Wm*Br is used when the circumferential width dimension of theinterconductor member at one magnetic pole is Wt, the saturationmagnetic flux density of the interconductor member is Bs, thecircumferential width dimension of the magnet unit at one magnetic poleis Wm, and the residual magnetic flux density of the magnet unit is Br.

B In the stator 50, an interconductor member is provided between eachconductor section in the circumferential direction, and a non-magneticmaterial is used as the interconductor member.

C The stator 50 has a configuration in which no interconductor member isprovided between each conductor section in the circumferentialdirection.

Further, the same applies to the magnets 91 and 92 of the magnet unit42. That is, the magnet unit 42 is composed with the use of the magnets91 and 92 in which, the orientation was made in such a manner that, onthe side of the d-axis, which is the center of the magnetic pole, thedirection of the axis of easy magnetization is parallel to the d-axis ascompared with the side of the q-axis, which is the magnetic poleboundary. Details such as the magnetization directions of the magnets 91and 92 are as described above. It is also possible to use the annularmagnet 95 (see FIG. 30) in the magnet unit 42.

FIG. 37 is a vertical cross-sectional view of the rotating electricmachine 10 in the case of an inner rotor type, which is a figurecorresponding to FIG. 2 described above. Differences from theconfiguration of FIG. 2 will be briefly described. In FIG. 37, anannular stator 50 is fixed to the inside of the housing 30, and a rotor40 is rotatably provided inside the stator 50 with a predetermined airgap therebetween. Similarly to FIG. 2, the respective bearings 21 and 22are arranged unevenly on either side in the axial direction with respectto the axial center of the rotor 40, whereby the rotor 40 iscantilevered and supported. Further, the inverter unit 60 is providedinside the magnet holder 41 of the rotor 40.

FIG. 38 illustrates another configuration of the rotating electricmachine 10 having an inner rotor structure. In FIG. 38, the rotatingshaft 11 is rotatably supported by the bearings 21 and 22 in the housing30, and the rotor 40 is fixed to the rotating shaft 11. Similarly to theconfiguration illustrated in FIG. 2 or the like, the respective bearings21 and 22 are arranged unevenly on either side in the axial directionwith respect to the axial center of the rotor 40. The rotor 40 has themagnet holder 41 and the magnet unit 42.

The rotating electric machine 10 of FIG. 38 is different from therotating electric machine 10 of FIG. 37 in that the inverter unit 60 isnot provided radially inside the rotor 40. The magnet holder 41 isconnected to the rotating shaft 11 at a position radially inside themagnet unit 42. Further, the stator 50 has the stator winding 51 and thestator core 52, and is attached to the housing 30.

Eleventh Modification

Another configuration as a rotating electric machine having an innerrotor structure will be described below. FIG. 39 is an explodedperspective view of a rotating electric machine 200, and FIG. 40 is aside sectional view of the rotating electric machine 200. Here, theup-down direction is illustrated with reference to the states of FIGS.39 and 40.

As illustrated in FIGS. 39 and 40, the rotating electric machine 200includes a stator 203 having an annular stator core 201 and amulti-phase stator winding 202, and a rotor 204 rotatably arrangedinside the stator core 201. The stator 203 corresponds to an armatureand the rotor 204 corresponds to a field magnet. The stator core 201 iscomposed by laminating a large number of silicon steel plates, and astator winding 202 is attached to the stator core 201. Although notillustrated, the rotor 204 has a rotor core and a plurality of permanentmagnets as a magnet unit. The rotor core is provided with a plurality ofmagnet insertion holes at equal intervals in the circumferentialdirection. Each of the magnet insertion holes is equipped with apermanent magnet magnetized in such a manner that the magnetizationdirection changes alternately for each adjacent magnetic pole. Moreover,the permanent magnet of the magnet unit may have a Halbach array asdescribed with reference to FIG. 23 or a similar configuration.Alternatively, it is preferable that the permanent magnet of the magnetunit has polar anisotropy characteristics such as that described withreference to FIG. 9 and FIG. 30, in which the orientation direction(magnetization direction) extends in an arc shape between the d-axiswhich is the center of the magnetic pole and the q-axis which is themagnetic pole boundary.

Here, the stator 203 preferably has any of the following configurations.

A In the stator 203, an interconductor member is provided between eachconductor section in the circumferential direction, and as theinterconductor member, a magnetic material having a relation ofWt*Bs≤Wm*Br is used when the width dimension of the interconductormember in the circumferential direction at one magnetic pole is Wt, thesaturation magnetic flux density of the interconductor member is Bs, thewidth dimension in the circumferential direction of the magnet unit atone magnetic pole is Win, and the residual magnetic flux density of themagnet unit is Br.

B In the stator 203, an interconductor member is provided between eachconductor section in the circumferential direction, and a non-magneticmaterial is used as the interconductor member.

C The stator 203 has a configuration in which no interconductor memberis provided between each conductor section in the circumferentialdirection.

Further, in the rotor 204, the magnet unit is composed with the use of aplurality of magnets in which, the orientation was made in such a mannerthat, on the side of the d-axis, which is the center of the magneticpole, the direction of the axis of easy magnetization is parallel to thed-axis as compared with the side of the q-axis, which is the magneticpole boundary.

An annular inverter case 211 is provided on one end side of the rotatingelectric machine 200 in the axial direction. The inverter case 211 isarranged in such a manner that the lower surface of the case is incontact with the upper surface of the stator core 201. Inside theinverter case 211, a plurality of power modules 212 constituting theinverter circuit, a smoothing capacitor 213 that suppressesvoltage/current pulsation (ripple) generated by the switching operationof the semiconductor switching element, a control board 214 having acontrol unit, a current sensor 215 that detects a phase current, and aresolver stator 216 that is a rotation speed sensor of the rotor 204 areprovided. The power module 212 has an IGBT and a diode which aresemiconductor switching elements.

On the periphery of the inverter case 211, a power connector 217connected to the DC circuit of the battery mounted on a vehicle, and asignal connector 218 used for transferring various signals between therotating electric machine 200 side and the vehicle side control deviceare provided. The inverter case 211 is covered with a top cover 219. Thedirect current power from a vehicle-mounted battery is input via thepower connector 217, converted into alternate current by switching ofthe power module 212, and sent to the stator winding 202 of each phase.

On both sides of the stator core 201 in the axial direction, on the sideopposite to the inverter case 211, a bearing unit 221 that rotatablyholds the rotating shaft of the rotor 204 and an annular rear case 222that houses the bearing unit 221 are provided. The bearing unit 221 has,for example, a pair of bearings and is arranged unevenly on either sidein the axial direction with respect to the axial center of the rotor204. However, a plurality of bearings in the bearing unit 221 may beprovided in a dispersed manner on both sides of the stator core 201 inthe axial direction, and the rotating shafts may be supported from bothsides by those respective bearings. The rotating electric machine 200can be mounted on the vehicle side by bolting and fixing the rear case222 to a mounting section such as a gear case or a transmission of thevehicle.

A cooling flow path 211 a for flowing a refrigerant is formed in theinverter case 211. The cooling flow path 211 a is formed by closing aspace recessed in an annular shape from the lower surface of theinverter case 211 with the upper surface of the stator core 201. Thecooling flow path 211 a is formed so as to surround the coil end of thestator winding 202. A module case 212 a of the power module 212 isinserted in the cooling flow path 211 a. Also in the rear case 222, acooling flow path 222 a is formed so as to surround the coil end of thestator winding 202. The cooling flow path 222 a is formed by closing aspace recessed in an annular shape from the upper surface of the rearcase 222 with the lower surface of the stator core 201.

Twelfth Modification

So far, the configuration embodied in the revolving-field type rotatingelectric machine has been described, but it is also possible to changethis and embody it in the rotating armature type rotating electricmachine. FIG. 41 illustrates the configuration of a rotating armaturetype rotating electric machine 230.

In the rotating electric machine 230 of FIG. 41, bearings 232 are fixedto housings 231 a and 231 b, respectively, and a rotating shaft 233 isrotatably supported by the bearings 232. The bearing 232 is, forexample, an oil-impregnated bearing made by impregnating a porous metalwith oil. A rotor 234 as an armature is fixed to the rotating shaft 233.The rotor 234 has a rotor core 235 and a multi-phase rotor winding 236fixed to the outer peripheral portion of the rotor core 235. In therotor 234, the rotor core 235 has a slotless structure, and the rotorwinding 236 has a flat conductor structure. That is, the rotor winding236 has a flat structure in which the region for each phase is longer inthe circumferential direction than in the radial direction.

Further, a stator 237 as a field magnet is provided radially outside therotor 234. The stator 237 has a stator core 238 fixed to the housing 231a and a magnet unit 239 fixed to the inner peripheral side of the statorcore 238. The magnet unit 239 has a configuration including a pluralityof magnetic poles having alternating polarities in the circumferentialdirection, and is configured similarly to the magnet unit 42 or the likedescribed above, in which, the orientation was made in such a mannerthat the direction of the axis of easy magnetization is parallel to thed-axis on the d-axis side which is the center of the magnetic pole ascompared with the q-axis side which is the magnetic pole boundary. Themagnet unit 239 has an oriented sintered neodymium magnet, the intrinsiccoercive force thereof is 400 [kA/m] or more, and the residual magneticflux density is 1.0 [T] or more.

The rotating electric machine 230 of this modification is a 2-pole3-coil brushed coreless motor, the rotor winding 236 is divided intothree, and the magnet unit 239 has two poles. The number of poles andthe number of coils of the brushed motor varies depending on theapplication, such as 2:3, 4:10, 4:21.

A commutator 241 is fixed to the rotating shaft 233, and a plurality ofbrushes 242 are arranged on the radially outside thereof. The commutator241 is electrically connected to the rotor winding 236 via a conductor243 embedded in the rotating shaft 233. A direct current flows in andout of the rotor winding 236 through these commutator 241, brush 242,and conductor 243. The commutator 241 is appropriately divided in thecircumferential direction in accordance with the number of phases of therotor winding 236. The brush 242 may be directly connected to a DC powersource such as a storage battery via an electrical wiring, or may beconnected to a DC power source via a terminal block or the like.

The rotating shaft 233 is provided with a resin washer 244 as a sealingmaterial between the bearing 232 and the commutator 241. The resinwasher 244 suppresses the oil seeping out from the bearing 232, which isan oil-impregnated bearing, from flowing out to the commutator 241 side.

Thirteenth Modification

In the stator winding 51 of the rotating electric machine 10, eachconductor wire 82 may have a plurality of insulating coatings inside andoutside. For example, it is preferable to bundle a plurality ofconductors (wires) with an insulating coating into one and cover theconductors with an outer layer coating to form the conductor wire 82. Inthis case, the insulating coating of the wire constitutes the innerinsulating coating, and the outer layer coating constitutes the outerinsulating coating. Further, in particular, it is preferable that theinsulating capability of the outer insulating coating among theplurality of insulating coatings on the conductor wire 82 is higher thanthe insulating capability of the inner insulating coating. Specifically,the thickness of the outer insulating coating is made thicker than thethickness of the inner insulating coating. For example, the thickness ofthe outer insulating coating is 100 μm, and the thickness of the innerinsulating coating is 40 μm. Alternatively, a material having a lowerdielectric constant than that of the inner insulating coating may beused as the outer insulating coating. At least one of these should beapplied. Moreover, it is preferable that the wire is configured as anaggregate of a plurality of conductive materials.

By strengthening the insulation of the outermost layer of the conductorwire 82 as described above, it becomes suitable for use in a highvoltage vehicle system. Further, the rotating electric machine 10 can beproperly driven even in highlands where the atmospheric pressure is low.

Fourteenth Modification

In the conductor wire 82 having a plurality of insulating coatingsinside and outside, at least one of the linear expansivity (linearexpansion coefficient) and the adhesive strength may be differentbetween the outer insulating coating and the inner insulating coating.The configuration of the conductor wire 82 in this modification isillustrated in FIG. 42.

In FIG. 42, the conductor wire 82 includes a plurality of (four in thefigure) wires 181, an outer layer coating 182 made of, for example, aresin (outer insulating coating), that surrounds the plurality of wires181, and an intermediate layer 183 (intermediate insulating coating)filled around each wire 181 in the outer layer coating 182. The wire 181has a conductive part 181 a made of a copper material and a conductorcoating 181 b (inner insulating coating) made of an insulating material.When viewed as a stator winding, the outer layer coating 182 insulatesthe phases. Moreover, it is preferable that the wire 181 is configuredas an aggregate of a plurality of conductive materials.

The intermediate layer 183 has a linear expansion coefficient higherthan that of the conductor coating 181 b of the wire 181 and a linearexpansion coefficient lower than that of the outer layer coating 182.That is, in the conductor wire 82, the linear expansion coefficient ishigher toward the outside. Generally, the outer layer coating 182 has alinear expansion coefficient higher than that of the conductor coating181 b, but by providing the intermediate layer 183 having anintermediate linear expansion coefficient between them, the intermediatelayer 183 functions as a cushioning material, and simultaneous crackingon the outer layer side and the inner layer side can be prevented.

Further, in the conductor wire 82, the conductive part 181 a and theconductor coating 181 b are adhered to each other in the wire 181, andthe conductor coating 181 b and the intermediate layer 183 and theintermediate layer 183 and the outer layer coating 182 are adhered toeach other, respectively, and the adhesive strength becomes weakertoward the outside of the conductor wire 82 in each of these adheredportions. That is, the adhesive strength of the conductive part 181 aand the conductor coating 181 b is weaker than the adhesive strength ofthe conductor coating 181 b and the intermediate layer 183 and theadhesive strength of the intermediate layer 183 and the outer layercoating 182. Further, comparing the adhesive strength of the conductorcoating 181 b and the intermediate layer 183 with the adhesive strengthof the intermediate layer 183 and the outer layer coating 182, it ispreferable that the latter (outer side) is weaker or equivalent.Moreover, the magnitude of the adhesive strength between the coatingscan be grasped from, for example, the tensile strength required whenpeeling off the two layers of coatings. By setting the adhesive strengthof the conductor wire 82 as described above, it is possible to suppresscracking (co-cracking) on both the inner layer side and the outer layerside even if an internal/external temperature difference occurs due toheat generation or cooling.

Here, the heat generation and temperature change of the rotatingelectric machine mainly occur as copper loss produced from theconductive part 181 a of the wire 181 and iron loss generated from theinside of the iron core, and these two types of losses are transmittedfrom the conductive part 181 a in the conductor wire 82 or the outsideof the conductor wire 82, and the intermediate layer 183 does not have aheat source. In this case, the intermediate layer 183 has an adhesiveforce that can serve as a cushion for both of them, and thussimultaneous cracking can be prevented. Consequently, suitable use ispossible even when used in fields with high withstand pressure or largetemperature changes such as vehicle applications.

This is supplemented below. The wire 181 may be, for example, an enamelwire, and in such a case, it has a resin coating layer (conductorcoating 181 b) such as PA, PI, and PAI. Further, it is desirable thatthe outer layer coating 182 outside the wire 181 is made of the same PA,PI, PAI, or the like, and has a large thickness. As a result, damage tothe coating due to a difference in linear expansion coefficient issuppressed. Moreover, as the outer layer coating 182, it is desirable toalso use one with a dielectric constant smaller than PI and PAI, such asPPS, PEEK, fluorine, polycarbonate, silicon, epoxy, polyethylenenaphthalate, and LCP, in addition to one made by thickening theaforementioned materials such as PA, PI, and PAI. With these resins,even if they are thinner than the PI and PAI coatings equivalent to theconductor coating 181 b or the thickness equivalent to the conductorcoating 181 b, their insulating capability can be enhanced, and it isthereby possible to increase the occupancy ratio of the conductive part.In general, the resin has better insulation than the insulating coatingof an enamel wire in terms of dielectric constant. As a matter ofcourse, there are cases where the dielectric constant is deteriorateddepending on the molding state and the mixture. Among them, PPS and PEEKare suitable as the outer layer coating of the second layer becausetheir linear expansion coefficient is generally larger than that of theenamel coating but smaller than that of other resins.

Further, it is desirable that the adhesive strength between the twotypes of coatings (intermediate insulating coating and outer insulatingcoating) on the outside of the wire 181 and the enamel coating on thewire 181 is weaker than the adhesive strength between the copper wireand the enamel coating on the wire 181. As a result, the phenomenon thatthe enamel coating and the aforementioned two types of coatings aredestroyed at once is suppressed.

In a case where a water-cooled structure, a liquid-cooled structure, oran air-cooled structure is added to the stator, it is considered thatthermal stress or impact stress is basically applied to the outer layercoating 182 first. However, even when the insulating layer of the wire181 and the resin of the two types of coatings are different, thermalstress and impact stress can be reduced by providing a portion where thecoatings are not adhered. That is, the aforementioned insulatedstructure is formed by providing a wire (enamel wire) and an space andarranging fluorine, polycarbonate, silicon, epoxy, polyethylenenaphthalate, and LCP. In this case, it is desirable to adhere the outerlayer coating and the inner layer coating with the use of an adhesivematerial made of epoxy or the like having a low dielectric constant andhaving a low linear expansion coefficient. By doing so, it is possibleto suppress not only the mechanical strength but also the destruction ofthe coating due to friction caused by the vibration of the conductivepart or the destruction of the outer layer coating due to a differencein the linear expansion coefficient.

As the outermost layer fixing which is generally the final processaround the stator winding, which is responsible for mechanical strength,fixing, and the like for the conductor wire 82 having the aboveconfiguration, resins such as epoxy, PPS, PEEK, and LCP, which have goodmoldability and have properties such as dielectric constant and linearexpansion coefficient similar to those of an enamel coating, arepreferable.

Generally, resin potting with urethane or silicon is usually performed,but the linear expansion coefficient of the aforementioned resin isalmost double that of other resins, and thermal stress capable ofshearing the resin is generated. Therefore, it is not suitable forapplications of 60V or higher where strict insulation regulations areused internationally. In this regard, according to the final insulationprocess for easily making by injection molding or the like using epoxy,PPS, PEEK, LCP or the like, each of the above requirements can beachieved.

Modifications other than the above are listed below.

-   -   A distance DM between the surface of the magnet unit 42 on the        armature side in the radial direction and the axial center of        the rotor in the radial direction may be 50 mm or more.        Specifically, a distance DM between, for example, the surface        radially inside the magnet unit 42 (specifically, the first and        second magnets 91 and 92) illustrated in FIG. 4 and the axial        center of the rotor 40 in the radial direction may be 50 mm or        more.

As a rotating electric machine having a slotless structure, asmall-scale one whose output is used for a model of several tens ofwatts to several hundreds of watts is known. In addition, the discloserof the present application does not grasp a case where the slotlessstructure is adopted in a large industrial rotating electric machinewhich generally exceeds 10 kW. The discloser of the present applicationexamined the reason.

In recent years, mainstream rotating electric machines are roughlyclassified into the following four types. These rotating electricmachines are a brushed motor, a basket type induction motor, a permanentmagnet type synchronous motor, and a reluctance motor.

An exciting current is supplied to the brushed motor via the brush.Therefore, in the case of a brushed motor of a large machine, the brushbecomes large and the maintenance becomes complicated. As a result, withthe remarkable development of semiconductor technology, it has beenreplaced by brushless motors such as induction motors. Meanwhile, in theworld of small motors, coreless motors are also supplied to the worldbecause of their low inertia and economic advantages.

In the basket type induction motor, the principle is that torque isgenerated by receiving the magnetic field generated by the statorwinding on the primary side by the iron core of the rotor on thesecondary side and intensively passing an induced current through thebasket type conductor to form a reaction magnetic field. Therefore, fromthe viewpoint of small size and high efficiency of equipment, it is notalways a good idea to eliminate the iron core on both the stator sideand the rotor side.

The reluctance motor is a motor that literally utilizes the reluctancechange of the iron core, and it is not desirable to eliminate the ironcore in principle.

In recent years. IPMs (that is, embedded magnet type rotors) have becomethe mainstream of permanent magnet type synchronous motors, and in largemachines in particular, IPMs are often used unless there are specialcircumstances.

The IPM has a characteristic of having both magnet torque and reluctancetorque, and is operated while the ratio of these torques is adjusted ina timely manner by inverter control. Therefore, the IPM is a small motorwith excellent controllability.

According to the analysis of the discloser of the present application,the torque on the rotor surface that generates magnet torque andreluctance torque is drawn with the horizontal axis of the distance DMin the radial direction between the surface of the magnet unit on thearmature side in the radial direction and the axial center of the rotor,that is, the radius of the stator core of a general inner rotor, asillustrated in FIG. 43.

The potential of the magnet torque is determined by the magnetic fieldstrength generated by the permanent magnet as indicated in the followingequation (eq1), whereas the potential of the reluctance torque isdetermined by the inductance, especially, the magnitude of the q-axisinductance as indicated in the following equation (eq2).

Magnet torque=k·ψ·Iq  (eq1)

Reluctance torque=k·(Lq−Ld)·Iq·Id  (eq2)

Here, the magnetic field strength of the permanent magnet and themagnitude of the inductance of the winding were compared by the DM. Themagnetic field strength generated by the permanent magnet, that is, theamount of magnetic flux ψ, is proportional to the total area of thepermanent magnet on the surface facing the stator. If a cylindricalrotor is used, it will be the surface area of the cylinder. Strictlyspeaking, since there are N pole and S pole, it is proportional to theoccupied area of half of the cylindrical surface. The surface area of acylinder is proportional to the radius of the cylinder and the length ofthe cylinder. That is, if the cylinder length is constant, it isproportional to the radius of the cylinder.

On the other hand, an inductance Lq of the winding depends on the shapeof the iron core but has low sensitivity, and is rather proportional tothe square of the number of turns of the stator winding, and thereforethe number of turns is highly dependent. Moreover, when μ is themagnetic permeability of the magnetic circuit, N is the number of turns,S is the cross-sectional area of the magnetic circuit, and δ is theeffective length of the magnetic circuit, the inductanceL=μ·N{circumflexover ( )}*S/δ. Since the number of turns of the winding depends on thesize of the winding space, in the case of a cylindrical motor, itdepends on the winding space of the stator, that is, the slot area. Asillustrated in FIG. 44, since the slot shape is substantiallyquadrangular, the slot area is proportional to the product a*b of alength dimension a in the circumferential direction and a lengthdimension b in the radial direction.

The circumferential length dimension of the slot is proportional to thediameter of the cylinder because it increases as the diameter of thecylinder increases. The radial length dimension of the slot is exactlyproportional to the diameter of the cylinder. That is, the slot area isproportional to the square of the diameter of the cylinder. Further, ascan be seen from the above equation (eq2), since the reluctance torqueis proportional to the square of the stator current, the performance ofthe rotating electric machine is determined by how large the current canflow, and that performance depends on the slot area of the stator. Fromthe above, if the length of the cylinder is constant, the reluctancetorque is proportional to the square of the diameter of the cylinder.Based on this, FIG. 43 is a diagram plotting the relation between themagnet torque and the reluctance torque and DM.

As illustrated in FIG. 43, the magnet torque increases linearly withrespect to the DM, and the reluctance torque increases quadraticallywith respect to the DM. It can be seen that the magnet torque isdominant when the DM is relatively small, and the reluctance torque isdominant as the stator core radius increases. The discloser of thepresent application has concluded that the intersection of the magnettorque and the reluctance torque in FIG. 43 is approximately in thevicinity of the stator core radius=50 mm under a predeterminedcondition. That is, it is difficult to eliminate the iron core in a 10kW class motor whose stator core radius sufficiently exceeds 50 mmbecause it is the current mainstream to utilize reluctance torque, andit is presumed that this is one of the reasons why the slotlessstructure is not adopted in the field of large machines.

In the case of a rotating electric machine in which an iron core is usedas a stator, magnetic saturation of the iron core is always an issue. Inparticular, in a radial gap type rotating electric machine, the verticalcross-sectional shape of the rotating shaft is a fan shape per magneticpole, the magnetic path width becomes narrower toward the innerperipheral side of the equipment, and the inner circumference sidedimension of the teeth portion forming the slot determines theperformance limit of the rotating electric machine. No matter howhigh-performance permanent magnets are used, if magnetic saturationoccurs in this portion, the performance of the permanent magnets cannotbe fully brought out. In order not to generate magnetic saturation inthis portion, the inner circumference must be designed to be large,resulting in an increase in the size of the equipment.

For example, in a distributed winding rotating electric machine, in thecase of a three-phase winding, the magnetic flux is shared by three tosix teeth per magnetic pole, but the magnetic flux tends to concentrateon the teeth in the front in the circumferential direction, and thus themagnetic flux does not flow evenly to the three to six teeth. In thiscase, while the magnetic flux flows intensively through some (forexample, one or two) teeth, the teeth that are magnetically saturatedwith the rotation of the rotor also move in the circumferentialdirection. This also causes slot ripple.

From the above, in a rotating electric machine having a slotlessstructure in which the DM is 50 mm or more, it is desired to abolish theteeth in order to eliminate magnetic saturation. However, when the teethare removed, the magnetic resistance of the magnetic circuit in therotor and the stator increases, and the torque of the rotating electricmachine decreases. The reason for the increase in magnetic resistanceis, for example, that the air gap between the rotor and the statorbecomes large. Therefore, in the above-mentioned rotating electricmachine having a slotless structure in which the DM is 50 mm or more,there is room for improvement in increasing the torque. Consequently,there is a great merit of applying the above-mentioned configurationcapable of increasing the torque to the above-mentioned rotatingelectric machine having a slotless structure in which the DM is 50 mm ormore.

Moreover, with regard to not only the rotating electric machine havingan outer rotor structure but also the rotating electric machine havingan inner rotor structure may have a distance DM of 50 mm or more in theradial direction between the surface of the magnet unit on the armatureside in the radial direction and the axial center of the rotor.

-   -   In the stator winding 51 of the rotating electric machine 10,        the straight section 83 of the conductor wire 82 may be provided        in a single layer in the radial direction. Further, when the        straight section 83 is arranged in a plurality of layers inside        and outside the radial direction, the number of layers may be        arbitrary, and may be provided in three layers, four layers,        five layers, six layers, and the like.    -   For example, in the configuration of FIG. 2, the rotating shaft        11 is provided so as to protrude to both one end side and the        other end side of the rotating electric machine 10 in the axial        direction, but this may be changed, and the rotating shaft 11        may be configured to protrude only to one end side. In this        case, the rotating shaft 11 may be provided so as to extend        outward in the axial direction, with a portion that is        cantilevered and supported by the bearing unit 20 as an end. In        this configuration, since the rotating shaft 11 does not        protrude inside the inverter unit 60, the internal space of the        inverter unit 60, specifically the internal space of the tubular        section 71, can be used more widely.    -   In the rotating electric machine 10 having the above        configuration, in the bearings 21 and 22, non-conductive grease        is used, but this may be changed, and conductive grease may be        used in the bearings 21 and 22. For example, conductive grease        containing metal particles, carbon particles, or the like is        used.    -   As a configuration for rotatably supporting the rotating shaft        11, bearings may be provided at two locations on one end side        and the other end side in the axial direction of the rotor 40.        In this case, in the configuration of FIG. 1, it is preferable        that bearings are provided at two locations on one end side and        the other end side with the inverter unit 60 therebetween.    -   In the rotating electric machine 10 having the above        configuration, in the rotor 40, the intermediate section 45 of        the magnet holder 41 has the inner shoulder section 49 a and the        annular outer shoulder section 49 b. However, these shoulder        sections 49 a and 49 b may be eliminated to have a flat surface.    -   In the rotating electric machine 10 having the above        configuration, the conductor 82 a is configured as an aggregate        of a plurality of wires 86 in the conductor wire 82 of the        stator winding 51, but this may be changed, and a square        conductor having a rectangular cross section may be used as the        conductor wire 82. Further, as the conductor wire 82, a round        conductor having a circular cross section or an elliptical cross        section may be used.    -   in the rotating electric machine 10 having the above        configuration, the inverter unit 60 is provided radially inside        the stator 50, but instead of this, the inverter unit 60 may not        be provided radially inside the stator 50. In this case, it is        possible to set an internal region inside the stator 50 in the        radial direction as a space. Further, it is possible to arrange        parts different from the inverter unit 60 in the internal        region.    -   The rotating electric machine 10 having the above configuration        may not include the housing 30. In this case, for example, the        rotor 40, the stator 50, and the like may be held in a part of        the wheel or other vehicle parts.

(Embodiment as an In-Wheel Motor for a Vehicle)

Next, an embodiment in which the rotating electric machine is providedintegrally with the wheels of a vehicle as an in-wheel motor will bedescribed. FIG. 45 is a perspective view illustrating a wheel 400 havingan in-wheel motor structure and its peripheral structure, FIG. 46 is avertical cross-sectional view of the wheel 400 and its peripheralstructure, and FIG. 47 is an exploded perspective view of the wheel 400.Each of these figures is a perspective view of the wheel 400 as viewedfrom the inside of the vehicle. Moreover, in the vehicle, the in-wheelmotor structure of the present embodiment can be applied in variousforms. For example, in a vehicle having two wheels in front of andbehind the vehicle, it is possible to apply the in-wheel motor structureof the present embodiment to the two wheels on the front side of thevehicle, the two wheels on the rear side of the vehicle, or the fourwheels on the front and rear of the vehicle. However, it can also beapplied to a vehicle in which at least one of the front and rear of thevehicle has one wheel. Moreover, the in-wheel motor is an applicationexample as a vehicle drive unit.

As illustrated in FIGS. 45 to 47, the wheel 400 includes, for example, atire 401 which is a well-known pneumatic tire, a wheel 402 fixed to theinner peripheral side of the tire 401, and a rotating electric machine500 fixed to the inner peripheral side of the wheel 402. The rotatingelectric machine 500 has a fixing section which is a section including astator and a rotation section which is a section including a rotor. Thefixing section is fixed to the vehicle body side, and the rotationsection is fixed to the wheel 402. The rotation of the rotation sectioncauses the tire 401 and the wheel 402 to rotate. Moreover, the detailedconfiguration of the rotating electric machine 500 including the fixingsection and the rotation section will be described below.

Further, as peripheral devices, a suspension device that holds the wheel400 with respect to a vehicle body (not illustrated), a steering devicethat changes the direction of the wheels 400, and a braking device thatbrakes the wheel 400 are attached to the wheel 400.

The suspension device is an independent suspension type suspension, andany type such as a trailing arm type, a strut type, a wishbone type, anda multi-link type can be applied. In the present embodiment, as thesuspension device, a lower arm 411 is provided so as to extend towardthe center side of the vehicle body, and a suspension arm 412 and aspring 413 are provided so as to extend in the up-down direction. Thesuspension arm 412 may be configured as, for example, a shock absorber.However, detailed illustration is omitted. The lower arm 411 and thesuspension arm 412 are respectively connected to the vehicle body sideand to a disk-shaped base plate 405 fixed to the fixing section of therotating electric machine 500. As illustrated in FIG. 46, the lower arm411 and the suspension arm 412 are supported on the rotating electricmachine S0 side (base plate 405 side) by support shafts 414 and 415 in acoaxial state with each other.

Further, as the steering device, for example, a rack & pinion typestructure, a ball & nut type structure, a hydraulic power steeringsystem, and an electric power steering system can be applied. In thepresent embodiment, a rack device 421 and a tie rod 422 are provided assteering devices, and the rack device 421 is connected to the base plate405 on the rotating electric machine 500 side via the tie rod 422. Inthis case, when the rack device 421 operates with the rotation of asteering shaft (not illustrated), the tie rod 422 moves in theright-left direction of the vehicle. As a result, the wheel 400 rotatesabout the support shafts 414 and 415 of the lower arm 411 and thesuspension arm 412, and the wheel direction is changed.

As the braking device, it is preferable to apply a disc brake or a drumbrake. In the present embodiment, as the braking device, a disc rotor431 fixed to a rotating shaft 501 of the rotating electric machine 500and a brake caliper 432 fixed to the base plate 405 on the rotatingelectric machine 500 side are provided. In the brake caliper 432, brakepads are operated by oil pressure or the like, and when the brake padsare pressed against the disc rotor 431, a braking force due to frictionis generated and the rotation of the wheel 400 is stopped.

Further, the wheel 400 is attached with a housing duct 440 that housesan electric wiring H1 extending from the rotating electric machine 500and a cooling pipe H2. The housing duct 440 extends from the end of therotating electric machine 500 on the fixing section side along the endface of the rotating electric machine 500 and is provided so as to avoidthe suspension arm 412, and is fixed to the suspension arm 412 in thatstate. As a result, the connection portion of the housing duct 440 inthe suspension arm 412 has a fixed positional relation with the baseplate 405. Therefore, it is possible to suppress the stress caused bythe vibration of the vehicle in the electric wiring H1 and the coolingpipe H2. Moreover, the electrical wiring H1 is connected to anin-vehicle power supply unit and an in-vehicle ECU (not illustrated),and the cooling pipe H2 is connected to a radiator (not illustrated).

Next, the configuration of the rotating electric machine 500 used as anin-wheel motor will be described in detail. In the present embodiment,an example in which the rotating electric machine 500 is applied to anin-wheel motor is indicated. The rotating electric machine 500 hasexcellent operating efficiency and output as compared with the motor ofa vehicle drive unit having a speed reducer as in the prior art. Thatis, if the rotating electric machine 500 is adopted in an application inwhich a practical price can be achieved by reducing the cost as comparedwith the prior art, it may be used as a motor for applications otherthan the vehicle drive unit. Even in such a case, it exhibits excellentperformance as when applied to an in-wheel motor. Moreover, theoperating efficiency refers to an index used during a test in a drivingmode that derives the fuel efficiency of a vehicle.

The outline of the rotating electric machine 500 is illustrated in FIGS.48 to 51. FIG. 48 is a side view of the rotating electric machine 500 asviewed from the protruding side (inside the vehicle) of the rotatingshaft 501, FIG. 49 is a vertical cross-sectional view of the rotatingelectric machine 500 (cross-sectional view taken along a line 49-49 ofFIG. 48), FIG. 50 is a cross-sectional view of the rotating electricmachine 500 (a cross-sectional view taken along a line 50-50 of FIG.49), and FIG. 51 is an exploded cross-sectional view of the componentsof the rotating electric machine 500. In the following description, inFIG. 51, the direction in which the rotating shaft 501 extends outwardof the vehicle body is the axial direction, the direction extendingradially from the rotating shaft 501 is the radial direction, and inFIG. 48, both of the two directions extending in a circumferential shapefrom any point other than the center of rotation of the rotating portionon the center line drawn to form a cross section 49 passing through thecenter of the rotating shaft 501, in other words, the center of rotationof the rotating portion are defined as the circumferential directions.In other words, the circumferential direction may be either a clockwisedirection starting from an arbitrary point on the cross section 49 or acounterclockwise direction. Further, in the vehicle-mounted state, theright side is the outside of the vehicle and the left side is the insideof the vehicle in FIG. 49. In other words, in the vehicle-mounted state,a rotor 510 which will be described below is arranged outward of thevehicle body with respect to a rotor cover 670.

The rotating electric machine 500 according to the present embodiment isan outer rotor type surface magnet type rotating electric machine. Therotating electric machine 500 includes, roughly, a rotor 510, a stator520, an inverter unit 530, a bearing 560, and the rotor cover 670. Eachof these members is arranged coaxially with the rotating shaft 501integrally provided on the rotor 510 and is assembled in the axialdirection in a predetermined order to form the rotating electric machine500.

In the rotating electric machine 500, the rotor 510 and the stator 520each have a cylindrical shape, and are arranged so as to face each otherwith an air gap therebetween. As the rotor 510 rotates integrally withthe rotating shaft 501, the rotor 510 rotates on the radial outside ofthe stator 520. The rotor 510 corresponds to a “field magnet” and thestator 520 corresponds to an “armature”.

The rotor 510 has a substantially cylindrical rotor carrier 511 and anannular magnet unit 512 fixed to the rotor carrier 511. The rotatingshaft 501 is fixed to the rotor carrier 511.

The rotor carrier 511 has a cylindrical section 513. A magnet unit 512is attached to the inner peripheral surface of the cylindrical section513. That is, the magnet unit 512 is provided in a state of beingsurrounded by the cylindrical section 513 of the rotor carrier 511 fromthe outside in the radial direction. Further, the cylindrical section513 has a first end and a second end facing each other in the axialdirection thereof. The first end is located in the direction outside thevehicle body, and the second end is located in the direction in whichthe base plate 405 is present. In the rotor carrier 511, an end plate514 is continuously provided at the first end of the cylindrical section513. That is, the cylindrical section 513 and the end plate 514 have anintegral structure. The second end of the cylindrical section 513 isopen. The rotor carrier 511 is formed of, for example, a steel platecold commercial having sufficient mechanical strength (SPCC or SPHCthicker than SPCC), forging steel, carbon fiber reinforced plastic(CFRP), or the like.

The axial length of the rotating shaft 501 is longer than the axialdimension of the rotor carrier 511. In other words, the rotating shaft501 protrudes toward the open end side (inward direction of the vehicle)of the rotor carrier 511, and the above-mentioned brake device or thelike is attached to the protruding side end.

A through hole 514 a is formed in the central portion of the end plate514 of the rotor carrier 511. The rotating shaft 501 is fixed to therotor carrier 511 in a state of being inserted into the through hole 514a of the end plate 514. The rotating shaft 501 has a flange 502extending in a direction intersecting with (orthogonal to) the axialdirection at a portion where the rotor carrier 511 is fixed, and in astate where the flange and the surface of the end plate 514 outside thevehicle are surface-joined, the rotating shaft 501 is fixed to the rotorcarrier 511. Moreover, in the wheel 400, the wheel 402 is fixed with theuse of a fastener such as a bolt erected from the flange 502 of therotating shaft 501 toward the outside of the vehicle.

Further, the magnet unit 512 is composed of a plurality of permanentmagnets arranged in such a manner that the polarities alternate alongthe circumferential direction of the rotor 510. As a result, the magnetunit 512 has a plurality of magnetic poles in the circumferentialdirection. The permanent magnet is fixed to the rotor carrier 511 by,for example, adhesion. The magnet unit 512 has the configurationdescribed as the magnet unit 42 with reference to FIGS. 8 and 9 of thefirst embodiment, and as a permanent magnet, has an intrinsic coerciveforce of 400 [kA/m] or more and is composed with a sintered neodymiummagnet having a residual magnetic flux Br of 1.0 [T] or more.

Similarly to the magnet unit 42 in FIG. 9 or the like, the magnet unit512 has a first magnet 91 and a second magnet 92, which are respectivelypolar anisotropic magnets and have different polarities from each other.As described with reference to FIGS. 8 and 9, each of the magnets 91 and92 has a different direction of the axis of easy magnetization on thed-axis side (the portion located near the d-axis) and the q-axis side(the portion located near the q-axis), and on the d-axis side, thedirection of the axis of easy magnetization is close to the directionparallel to the d-axis, and on the q-axis side, the direction of theeasy magnetization axis is close to the direction orthogonal to theq-axis. In addition, an arc-shaped magnet magnetic path is formed by theorientation according to the direction of the axis of easymagnetization. Moreover, in each of the magnets 91 and 92, the axis ofeasy magnetization may be oriented parallel to the d-axis on the d-axisside, and the axis of easy magnetization may be oriented orthogonal tothe q-axis on the q-axis side. In short, the magnet unit 512 isconfigured, in which the orientation was made in such a manner that thedirection of the axis of easy magnetization is parallel to the d-axis onthe d-axis side which is the center of the magnetic pole as comparedwith the q-axis side which is the magnetic pole boundary.

According to the magnets 91 and 92, the magnet magnetic flux on thed-axis is strengthened and the change in magnetic flux near the q-axisis suppressed. As a result, the magnets 91 and 92 in which the change insurface magnetic flux from the q-axis to the d-axis at each magneticpole is gentle can be preferably achieved. As the magnet unit 512, theconfigurations of the magnet unit 42 illustrated in FIGS. 22 and 23 andthe configuration of the magnet unit 42 illustrated in FIG. 30 can alsobe used.

Moreover, the magnet unit 512 may have a rotor core (back yoke) formedby laminating a plurality of electromagnetic steel sheets in the axialdirection on the side of the cylindrical section 513 of the rotorcarrier 511, that is, on the outer peripheral surface side. That is, itis also possible to provide a rotor core on the radial inside of thecylindrical section 513 of the rotor carrier 511 and to provide thepermanent magnets (magnets 91 and 92) on the radial inside of the rotorcore.

As illustrated in FIG. 47, the cylindrical section 513 of the rotorcarrier 511 is formed with a recess 513 a in a direction extending inthe axial direction at predetermined intervals in the circumferentialdirection. The recess 513 a is formed by, for example, press working,and as illustrated in FIG. 52, a protrusion 513 b is formed on the innerperipheral surface side of the cylindrical section 513 at a position onthe back side of the recess 513 a. On the other hand, on the outerperipheral surface side of the magnet unit 512, a recess 512 a is formedin accordance with the protrusion 513 b of the cylindrical section 513,and the protrusion 513 b of the cylindrical section 513 enters therecess 512 a, whereby the displacement in the circumferential directionof the magnet unit 512 is suppressed. That is, the protrusion 513 b onthe rotor carrier 511 side functions as the rotation stop section of themagnet unit 512. Moreover, the method for forming the protrusion 513 bmay be any method other than press working.

In FIG. 52, the direction of the magnet magnetic path in the magnet unit512 is indicated by an arrow. The magnet magnetic path extends in an arcshape so as to straddle the q-axis which is the magnetic pole boundary,and is in a direction parallel to or close to parallel to the d-axis onthe d-axis which is the center of the magnetic pole. The magnet unit 512is formed with a recess 512 b at positions corresponding to the q-axison the inner peripheral surface side thereof. In this case, in themagnet unit 512, the magnet magnetic path length differs between theside closer to the stator 520 (lower side in the figure) and the sidefarther from the stator 520 (upper side in the figure), the magnetmagnetic path length is shorter on the side closer to the stator 520,and the recess 512 b is formed at a position where the magnet magneticpath length is the shortest. That is, in consideration of the fact thatit is difficult for the magnet unit 512 to generate a sufficient magnetmagnetic flux in a place where the magnet magnetic path length is short,the magnet is omitted in a place where the magnet magnetic flux is weak.

Here, an effective magnetic flux density Bd of the magnet becomes higheras the length of the magnetic circuit passing through the inside of themagnet becomes longer. Further, a permeance coefficient Pc and theeffective magnetic flux density Bd of the magnet are in a relation thatthe higher one is, the higher the other is. According to theconfiguration of FIG. 52, the amount of magnets can be reduced whilesuppressing a decrease in the permeance coefficient Pc which is an indexof the height of the effective magnetic flux density Bd of the magnet.Moreover, in a B-H coordinates, the intersection of the permeancestraight line and the demagnetization curve according to the shape ofthe magnet is the operating point, and the magnetic flux density at theoperating point is the effective magnetic flux density Bd of the magnet.The rotating electric machine 500 of the present embodiment has aconfiguration in which the amount of iron in the stator 520 is reduced,and in such a configuration, a method for setting a magnetic circuitstraddling the q-axis is extremely effective.

Further, the recess 512 b of the magnet unit 512 can be used as an airpassage extending in the axial direction. Therefore, it is also possibleto improve the air cooling performance.

Next, the configuration of the stator 520 will be described. The stator520 has a stator winding 521 and a stator core 522. FIG. 53 is aperspective view illustrating the stator winding 521 and the stator core522 in an exploded manner.

The stator winding 521 is composed of a plurality of phase windingsformed by winding in a substantially tubular shape (annular shape), andthe stator core 522 as a base member is assembled radially inside thestator winding 521. In the present embodiment, a U-phase, V-phase, andW-phase windings are used, and the stator winding 521 is therebyconfigured as a three-phase winding. Each phase winding is composed oftwo inner and outer layers of conductors 523 in the radial direction.Similarly to the stator 50 described above, the stator 520 ischaracterized by having a slotless structure and a flat conductorstructure of the stator winding 521, and has the same configuration asor a configuration similar to that of the stator 50 illustrated in FIGS.8 to 16.

The configuration of the stator core 522 will be described. Similarly tothe stator core 52 described above, the stator core 522 has acylindrical shape in which a plurality of electromagnetic steel sheetsare laminated in the axial direction and has a predetermined thicknessin the radial direction, and the stator winding 521 is assembled on theradially outside that is the rotor 510 side in the stator core 522. Theouter peripheral surface of the stator core 522 has a curved shapewithout unevenness, and in a state where the stator winding 521 isassembled, the conductor 523 constituting the stator winding 521 arearranged side by side in the circumferential direction on the outerperipheral surface of the stator core 522. The stator core 522 functionsas a back core.

The stator 520 may use any of the following A to C.

A In the stator 520, an interconductor member is provided between eachconductor 523 in the circumferential direction, and as theinterconductor member, a magnetic material having a relation ofWt*Bs≤Wm*Br is used when the width dimension of the interconductormember in the circumferential direction at one magnetic pole is Wt, thesaturation magnetic flux density of the interconductor member is Bs, thewidth dimension in the circumferential direction of the magnet unit 512at one magnetic pole is Wm, and the residual magnetic flux density ofthe magnet unit 512 is Br.

B In the stator 520, an interconductor member is provided between eachconductor 523 in the circumferential direction, and a non-magneticmaterial is used as the interconductor member.

C The stator 520 has a configuration in which no interconductor memberis provided between each conductor 523 in the circumferential direction.

According to such configuration of the stator 520, the inductance can bereduced as compared with a rotating electric machine having a generalteeth structure in which teeth (iron core) for establishing a magneticpath is provided between respective conductor sections as a statorwinding. Specifically, the inductance can be reduced to 1/10 or less. Inthis case, since the impedance decreases as the inductance decreases,the output power with respect to the input power of the rotatingelectric machine 500 can be increased, which thus can contribute to theincrease in torque. Further, it is possible to provide a rotatingelectric machine with a higher output than a rotating electric machineusing an embedded magnet type rotor that outputs torque utilizing thevoltage of the impedance component (in other words, utilizing reluctancetorque).

In the present embodiment, the stator winding 521 is integrally moldedtogether with the stator core 522 by a molding material (insulatingmember) made of resin or the like, and the molding material isinterposed between the respective conductors 523 arranged in thecircumferential direction. According to such a configuration, the stator520 of the present embodiment corresponds to the configuration of Bamong the above A to C. Further, the respective conductors 523 adjacentto each other in the circumferential direction are arranged in such amanner that the end faces in the circumferential direction are incontact with each other or are arranged close to each other at a minuteinterval, and the configuration of the above C may be adopted in view ofthis configuration. Moreover, in a case where the configuration A isadopted, it is preferable that a protrusion is provided on the outerperipheral surface of the stator core 522, in accordance with thedirection of the conductor 523 in the axial direction, that is, inaccordance with the skew angle of the stator winding 521 having a skewstructure, for example.

Next, the configuration of the stator winding 521 will be described withreference to FIG. 54. FIG. 54 is a front view illustrating the statorwinding 521 developed in a plane, FIG. 54A illustrates each conductor523 located in the outer layer in the radial direction, and FIG. 54Billustrates each conductor 523 located in the inner layer in the radialdirection.

The stator winding 521 is formed being wound in an annular shape bydistributed winding. In the stator winding 521, the conductor materialis wound around the inner and outer two layers in the radial direction,and the respective conductors 523 on the inner layer side and the outerlayer side are skewed in different directions (See FIGS. 54A and 54B).The respective conductors 523 are insulated from each other. It ispreferable that the conductor 523 is configured as an aggregate of aplurality of wires 86 (see FIG. 13). Further, for example, twoconductors 523 having the same phase and the same energizing directionare provided side by side in the circumferential direction. In thestator winding 521, one conductor section having the same phase iscomposed of each conductor 523 having two layers in the radial directionand two conductors in the circumferential direction (that is, a total offour conductors), and the conductor section is provided one per magneticpole.

It is desirable that the radial thickness dimension of the conductorsection be smaller than the circumferential width dimension for onephase in one magnetic pole, whereby the stator winding 521 has a flatconductor structure. Specifically, for example, in the stator winding521, one conductor section having the same phase is preferably composedof each conductor 523 having two layers in the radial direction and fourconductors in the circumferential direction (that is, a total of eightconductors). Alternatively, in the conductor cross section of the statorwinding 521 illustrated in FIG. 50, the circumferential width dimensionis preferably larger than the radial thickness dimension. As the statorwinding 521, the stator winding 51 illustrated in FIG. 12 can also beused. However, in this case, it is necessary to secure a space in therotor carrier 511 for housing the coil end of the stator winding.

In the stator winding 521, the conductors 523 are arranged side by sidein the circumferential direction, being tilted at a predetermined angleon a coil side 525 that overlaps the stator core 522 inside and outsidethe radial direction, and coil ends 526 on both sides, which are axiallyouter than the stator core 522, are inverted (folded back) inward in theaxial direction to form a continuous connection. FIG. 54A illustrates arange of the coil side 525 and a range of the coil end 526,respectively. The inner layer side conductor 523 and the outer layerside conductor 523 are connected to each other at the coil end 526, andas a result, each time the conductor 523 is inverted in the axialdirection at the coil end 526 (each time it is folded back), theconductor 523 is switched alternately between the inner layer side andthe outer layer side. In short, the stator winding 521 has aconfiguration in which the inner and outer layers are switched inaccordance with the reversal of the direction of the current in therespective conductors 523 that are continuous in the circumferentialdirection.

Further, in the stator winding 521, two types of skews are applied inwhich the skew angles are different between the end regions that areboth ends in the axial direction and the central region sandwichedbetween the end regions. That is, as illustrated in FIG. 55, in theconductor 523, a skew angle θs1 in the central region and a skew angleθs2 in the end region are different, and the skew angle θs1 is smallerthan the skew angle θs2. In the axial direction, the end region isdefined to include the coil side 525. The skew angle θs1 and the skewangle θs2 are tilt angles at which each conductor 523 is tilted withrespect to the axial direction. The skew angle θs1 in the central regionmay be set in an angle range appropriate for reducing the harmoniccomponent of the magnetic flux generated by the energization of thestator winding 521.

The skew angle of each conductor 523 in the stator winding 521 is madedifferent between the central region and the end region, and the skewangle θs1 in the central region is made smaller than the skew angle θs2in the end region, whereby the winding coefficient of the stator winding521 can be increased while reducing the coil end 526. In other words,the length of the coil end 526, that is, the conductor length of theportion protruding in the axial direction from the stator core 522, canbe shortened while ensuring a desired winding coefficient. As a result,it is possible to improve the torque while downsizing the rotatingelectric machine 500.

Here, an appropriate range as the skew angle θs1 in the central regionwill be described. When X conductors 523 are arranged in one magneticpole in the stator winding 521, it is conceivable that the Xth orderharmonic component is generated by energization of the stator winding521. When the number of phases is S and the logarithm is m, X=2*S*m. Thediscloser of the present application focused on the fact that the Xthorder harmonic component is a component that constitutes a compositewave of the X−1th order harmonic component and the X+1th order harmoniccomponent, and therefore at least one of the X−1th order harmoniccomponent or the X+1th order harmonic component is reduced, whereby theXth order harmonic component can be reduced. Based on this focus, thediscloser of the present application found that the skew angle θs1 isset within the angle range of “360°/(X+1) to 360°/(X−1)” in terms of theelectrical angle, whereby the Xth harmonic component can be reduced.

For example, when S=3 and m=2, the skew angle θs1 is set within theangle range of “360°/13 to 360°/11” in order to reduce the harmoniccomponent of the X=12th order. That is, the skew angle θs1 is preferablyset at an angle within the range of 27.7° to 32.7°.

By setting the skew angle θs1 in the central region as described above,the magnet magnetic fluxes alternated at N and S poles can be positivelyinterlinked in the central region, and the winding coefficient of thestator winding 521 can be increased.

The skew angle θs2 in the end region is larger than the skew angle θs1in the central region described above. In this case, the angle range ofthe skew angle θs2 is “θs1<θs2<90°”.

Further, in the stator winding 521, the inner layer side conductor 523and the outer layer side conductor 523 are preferably connected bywelding or adhesion between the ends of the respective conductors 523,or are preferably connected by bending. In the stator winding 521, theend of each phase winding is electrically connected to a power converter(inverter) via a bus bar or the like on one side (that is, one end sidein the axial direction) of each coil end 526 on both sides in the axialdirection. Therefore, here, the configuration in which the respectiveconductors are connected to each other at the coil end 526 will bedescribed while distinguishing between the coil end 526 on the bus barconnection side and the coil end 526 on the opposite side.

The first configuration is such that each conductor 523 is connected atthe coil end 526 on the bus bar connection side by welding, and eachconductor 523 is connected at the coil end 526 on the opposite side bymeans other than welding. As the means other than welding, for example,a connection by bending a conductor material is conceivable. At the coilend 526 on the bus bar connection side, it is assumed that the bus baris connected to the end of each phase winding by welding. Therefore, byconnecting each conductor 523 at the same coil end 526 by welding, eachwelded portion can be handled in a series of processes, and workefficiency can be improved.

The second configuration is such that each conductor 523 is connected atthe coil end 526 on the bus bar connection side by means other thanwelding, and each conductor 523 is connected at the coil end 526 on theopposite side by welding. In this case, if each conductor 523 isconnected at the coil end 526 on the bus bar connection side by welding,the separation distance between the bus bar and the coil end 526 needsto be sufficient to avoid contact between the welded portion and the busbar. However, with this configuration, the separation distance betweenthe bus bar and the coil end 526 can be reduced. As a result, theregulation regarding the length of the stator winding 521 in the axialdirection or the bus bar can be relaxed.

As the third configuration, each conductor 523 is connected at the coilends 526 on both sides in the axial direction by welding. In this case,all of the conductor materials prepared before welding may have a shortwire length, and the work efficiency can be improved by reducing thebending process.

As the fourth configuration, each conductor 523 is connected at the coilends 526 on both sides in the axial direction by means other thanwelding. In this case, the portion of the stator winding 521 to bewelded can be reduced as much as possible, and the concern thatinsulation peeling may occur in the welding process can be reduced.

Further, in the process of manufacturing the annular stator winding 521,it is preferable to manufacture the strip-shaped windings arranged in aplane shape, and then to form the strip-shaped windings in an annularshape. In this case, it is preferable to weld the conductors at the coilend 526 in a state where the winding is a flat strip. When forming aflat strip-shaped winding in an annular shape, it is preferable to use acylindrical jig having the same diameter as that of the stator core 522and wind the strip-shaped winding around the cylindrical jig to form thestrip-shaped winding in an annular shape. Alternatively, thestrip-shaped winding may be wound directly around the stator core 522.

Moreover, the configuration of the stator winding 521 can also bechanged as follows.

For example, in the stator winding 521 illustrated in FIGS. 54A and 54B,the skew angles of the central region and the end region may be thesame.

Further, in the stator windings 521 illustrated in FIGS. 54A and 54B,the ends of the in-phase conductors 523 adjacent to each other in thecircumferential direction may be connected by a crossover sectionextending in a direction orthogonal to the axial direction.

The number of layers of the stator winding 521 may be 2*n layers (n is anatural number), and the stator winding 521 may have 4 layers, 6 layers,or the like in addition to the 2 layers.

Next, the inverter unit 530, which is a power conversion unit, will bedescribed. Here, the configuration of the inverter unit 530 will bedescribed with reference to FIGS. 56 and 57, which are explodedcross-sectional views of the inverter unit 530. Moreover, in FIG. 57,each member illustrated in FIG. 56 is illustrated as two subassemblies.

The inverter unit 530 includes an inverter housing 531, a plurality ofelectric modules 532 assembled to the inverter housing 531, and a busbar module 533 that electrically connects each of the electric modules532.

The inverter housing 531 has a cylindrical outer wall member 541, aninner wall member 542 having a cylindrical outer peripheral diametersmaller than that of the outer wall member 541 and arranged radiallyinside the outer wall member 541, and a boss forming member 543 fixed toone end side in the axial direction of the inner wall member 542. Eachof these members 541 to 543 is preferably made of a conductive material,for example, made of carbon fiber reinforced plastic (CFRP). Theinverter housing 531 is configured by combining the outer wall member541 and the inner wall member 542 inside and outside the radialdirection, and assembling the boss forming member 543 on one end side inthe axial direction of the inner wall member 542. The assembled state isthe state illustrated in FIG. 57.

The stator core 522 is fixed to the radial outside of the outer wallmember 541 of the inverter housing 531. As a result, the stator 520 andthe inverter unit 530 are integrated.

As illustrated in FIG. 56, the outer wall member 541 is formed with aplurality of recesses 541 a, 541 b, and 541 c on the inner peripheralsurface thereof, and the inner wall member 542 is formed with aplurality of recesses 542 a, 542 b, and 542 c on the outer peripheralsurface thereof, in addition, by the outer wall member 541 and the innerwall member 542 being assembled to each other, three hollow portions 544a. 544 b, and 544 c are formed between them (see FIG. 57). Of these, thecentral hollow portion 544 b is used as a cooling water passage 545through which cooling water as a refrigerant flows. Further, a sealingmaterial 546 is housed in the hollow portions 544 a and 544 c on bothsides of the hollow portion 544 b (cooling water passage 545). Thehollow portion 544 b (cooling water passage 545) is sealed by thesealing material 546. The cooling water passage 545 will be described indetail below.

Further, the boss forming member 543 is provided with a disc ring-shapedend plate 547 and a boss section 548 protruding from the end plate 547toward the inside of the housing. The boss section 548 is provided in ahollow tubular shape. For example, as illustrated in FIG. 51, the bossforming member 543 is fixed to the second end, of the first end of theinner wall member 542 in the axial direction and the second end on theprotruding side (that is, inside the vehicle) of the rotating shaft 501facing the first end. Moreover, in the wheels 400 illustrated in FIGS.45 to 47, the base plate 405 is fixed to the inverter housing 531 (morespecifically, the end plate 547 of the boss forming member 543).

The inverter housing 531 has a configuration having a double peripheralwall in the radial direction about the shaft center, and the outerperipheral wall of the double peripheral wall is formed by the outerwall member 541 and the inner wall member 542, and the inner peripheralwall is formed by the boss section 548. Moreover, in the followingdescription, the outer peripheral wall formed by the outer wall member541 and the inner wall member 542 is also referred to as an “outerperipheral wall WA1”, and the inner peripheral wall formed by the bosssection 548 is also referred to as an “inner peripheral wall WA2”.

An annular space is formed in the inverter housing 531 between the outerperipheral wall WA1 and the inner peripheral wall WA2, and a pluralityof electric modules 532 are arranged side by side in the circumferentialdirection in the annular space. The electric module 532 is fixed to theinner peripheral surface of the inner wall member 542 by adhesion, screwtightening, or the like. In the present embodiment, the inverter housing531 corresponds to a “housing member” and the electric module 532corresponds to an “electric component”.

A bearing 560 is housed inside the inner peripheral wall WA2 (bosssection 548), and the rotating shaft 501 is rotatably supported by thebearing 560. The bearing 560 is a hub bearing that rotatably supportsthe wheel 400 at the center of the wheel. The bearing 560 is provided ata position overlapping with the rotor 510, the stator 520, and theinverter unit 530 in the axial direction. In the rotating electricmachine 500 of the present embodiment, the magnet unit 512 can be madethinner in accordance with the orientation of the rotor 510, and aslotless structure or a flat conductor structure is adopted in thestator 520. Thus, it is possible to expand the hollow space radiallyinside the magnetic circuit section by reducing the radial thicknessdimension of the magnetic circuit section. This makes it possible toarrange the magnetic circuit section, the inverter unit 530, and thebearing 560 in a state of being stacked in the radial direction. Theboss section 548 is a bearing holding section that holds the bearing 560thereinside.

The bearing 560 is, for example, a radial ball bearing, and has atubular inner ring 561, an outer ring 562 having a diameter larger thanthat of the inner ring 561 and arranged radially outside the inner ringS61, and a plurality of balls 563 arranged between the inner ring 561and the outer ring 562. The bearing 560 is fixed to the inverter housing531 by assembling the outer ring 562 to the boss forming member 543, andthe inner ring 561 is fixed to the rotating shaft 501. The inner ring561, outer ring 562, and ball 563 are all made of a metallic materialsuch as carbon steel.

Further, the inner ring 561 of the bearing 560 has a tubular section 561a that houses the rotating shaft 501 and a flange 561 b that extends ina direction intersecting with (orthogonal to) the axis direction fromone end in the axial direction of the tubular section 561 a. The flange561 b is a portion that comes into contact with the end plate 514 of therotor carrier 511 from the inside, and in a state where the bearing 560is assembled to the rotating shaft 501, the rotor carrier 511 is held ina state of being sandwiched between the flange 502 of the rotating shaft501 and the flange 561 b of the inner ring 561. In this case, the flange502 of the rotating shaft 501 and the flange 561 b of the inner ring 561have the same angle of intersection with respect to the axial direction(both are right angles in the present embodiment), and the rotor carrier511 is held in a state of being sandwiched between these respectiveflanges 502 and 561 b.

According to the configuration in which the rotor carrier 511 issupported from the inside by the inner ring 561 of the bearing 560, theangle of the rotor carrier 511 with respect to the rotating shaft 501can be maintained at an appropriate angle, and thus the parallelism ofthe magnet unit 512 with respect to the rotating shaft 501 can be keptgood. As a result, even if the rotor carrier 511 is expanded in theradial direction, the resistance to vibration and the like can beenhanced.

Next, the electric module 532 housed in the inverter housing 531 will bedescribed.

The plurality of electric modules 532 are obtained by dividing electriccomponents such as semiconductor switching elements and smoothingcapacitors constituting a power converter into a plurality of individualmodules. The electric module 532 includes a switch module 532A having asemiconductor switching element that is a power element and a capacitormodule 532B having a smoothing capacitor.

As illustrated in FIGS. 49 and 50, a plurality of spacers 549 having aflat surface for attaching the electric module 532 are fixed to theinner peripheral surface of the inner wall member 542, and the electricmodule 532 is attached to the spacer 549. That is, the inner peripheralsurface of the inner wall member 542 is a curved surface, whereas themounting surface of the electric module 532 is a flat surface, and thusthe spacer 549 forms a flat surface on the inner peripheral surface sideof the inner wall member 542, and the electric module 532 is fixed tothe flat surface.

Note that the configuration in which the spacer 549 is interposedbetween the inner wall member 542 and the electric module 532 is notessential, and it is also possible to attach the electric module 532directly to the inner wall member 542 by flattening the inner peripheralsurface of the inner wall member 542 or by making the mounting surfaceof the electric module 532 curved. Further, it is also possible to fixthe electric module 532 to the inverter housing 531 in a state ofnon-contact with the inner peripheral surface of the inner wall member542. For example, the electric module 532 is fixed to the end plate 547of the boss forming member 543. It is also possible to fix the switchmodule 532A to the inner peripheral surface of the inner wall member 542in a contact state, and to fix the capacitor module 532B to the innerperipheral surface of the inner wall member 542 in a non-contact state.

Moreover, in a case where the spacer 549 is provided on the innerperipheral surface of the inner wall member 542, the outer peripheralwall WA1 and the spacer 549 correspond to the “tubular section”.Further, in a case where the spacer 549 is not used, the outerperipheral wall WA1 corresponds to the “tubular section”.

As described above, the outer peripheral wall WA1 of the inverterhousing 531 is formed with the cooling water passage 545 through whichcooling water as a refrigerant flows, and each electric module 532 iscooled by the cooling water flowing through the cooling water passage545. Moreover, it is also possible to use cooling oil as the refrigerantas an alternative to the cooling water. The cooling water passage 545 isprovided in an annular shape along the outer peripheral wall WA1, andthe cooling water flowing in the cooling water passage 545 flows fromthe upstream side to the downstream side while passing through eachelectric module 532. In the present embodiment, the cooling waterpassage 545 is provided in an annular shape so as to overlap eachelectric module 532 inside and outside the radial direction and tosurround these respective electric modules 532.

The inner wall member 542 is provided with an inlet passage 571 forflowing the cooling water into the cooling water passage 545 and anoutlet passage 572 for discharging the cooling water from the coolingwater passage 545. As described above, the plurality of electric modules532 are fixed to the inner peripheral surface of the inner wall member542, and in such a configuration, the interval between the electricmodules adjacent to each other in the circumferential direction isexpanded in only one place, and a part of the inner wall member 542 isprotruded inward in the radial direction to form a protruding section573 in the expanded portion. In addition, the protruding section 573 isprovided with the inlet passage 571 and the outlet passage 572 in aside-by-side manner along the radial direction.

FIG. 58 illustrates a state of arrangement of each electric module 532in the inverter housing 531. Note that FIG. 58 is the same verticalcross-sectional view as FIG. 50.

As illustrated in FIG. 58, the respective electric modules 532 arearranged side by side in the circumferential direction with the intervalbetween the electric modules in the circumferential direction as a firstinterval INT1 or a second interval INT2. The second interval INT2 is awider interval than the first interval INT1. The respective intervalsINT1 and INT2 are, for example, the distance between the centerpositions of two electric modules 532 adjacent to each other in thecircumferential direction. In this case, the interval between theelectric modules adjacent to each other in the circumferential directionwithout sandwiching the protruding section 573 is the first intervalINT1, and the interval between the electric modules adjacent to eachother in the circumferential direction sandwiching the protrudingsection 573 is the second interval INT2. That is, the interval betweenthe electric modules adjacent to each other in the circumferentialdirection is partially widened, and the protruding section 573 isprovided at, for example, the central portion of the widened interval(second interval INT2).

The respective intervals INT1 and INT2 may be, for example, the distanceof an are between the center positions of two electric modules 532adjacent to each other in the circumferential direction, on the samecircle centered on the rotating shaft 501. Alternatively, the intervalbetween the electric modules in the circumferential direction may bedefined by angular distances θi1 and θi2 centered on the rotating shaft501 (θi1<θi2).

Moreover, in the configuration illustrated in FIG. 58, the respectiveelectric modules 532 arranged at the first interval INT1 are arranged ina state of being separated from each other in the circumferentialdirection (non-contact state), but instead of this configuration, therespective electric modules 532 may be arranged in the circumferentialdirection in a state of being in contact with each other.

As illustrated in FIG. 48, the end plate 547 of the boss forming member543 is provided with a water channel port 574 in which the passage endsof the inlet passage 571 and the outlet passage 572 are formed. Acirculation path 575 for circulating cooling water is connected to theinlet passage 571 and the outlet passage 572. The circulation path 575is compose of a cooling water pipe. A pump 576 and a heat radiatingdevice 577 are provided in the circulation path 575, and the coolingwater circulates through the cooling water passage 545 and thecirculation path 575 as the pump 576 is driven. The pump 576 is anelectric pump. The heat radiating device 577 is, for example, a radiatorthat releases the heat of the cooling water to the atmosphere.

As illustrated in FIG. 50, since the stator 520 is arranged on theoutside of the outer peripheral wall WA1 and the electric module 532 isarranged on the inside of the outer peripheral wall WA1, the heat of thestator 520 is transferred to the outer peripheral wall WA1 from theoutside, and the heat of the electric module 532 is transferred from theinside. In this case, the stator 520 and the electric module 532 can becooled at the same time by the cooling water flowing the cooling waterpassage 545, and the heat of the heat-generating component in therotating electric machine 500 can be efficiently released.

Here, the electrical configuration of the power converter will bedescribed with reference to FIG. 59.

As illustrated in FIG. 59, the stator winding 521 is composed of aU-phase winding, a V-phase winding, and a W-phase winding, and aninverter 600 is connected to the stator winding 521. The inverter 600 iscomposed of a full bridge circuit having the same number of upper andlower arms as the number of phases, and a series connection bodycomposed of an upper arm switch 601 and a lower arm switch 602 isprovided for each phase. These respective switches 601 and 602 areturned on/off by the drive circuit 603, and the winding of each phase isenergized by the on/off. The respective switches 601 and 602 arecomposed of a semiconductor switching element such as a MOSFET or anIGBT. Further, in the upper and lower arms of each phase, a chargesupply capacitor 604 that supplies the charge required for switching tothe respective switches 601 and 602 is connected in parallel to theseries connection body of the switches 601 and 602.

A control device 607 includes a microcomputer composed of a CPU andvarious memories, and performs energization control by turning on/offthe respective switches 601 and 602 on the basis of various detectedinformation in the rotating electric machine 500 and requests for powerrunning and power generation. The control device 607 performs on/offcontrol of the respective switches 601 and 602 by, for example, PWMcontrol at a predetermined switching frequency (carrier frequency) andrectangular wave control. The control device 607 may be a built-incontrol device built in the rotating electric machine 500, or anexternal control device provided outside the rotating electric machine500.

Incidentally, in the rotating electric machine 500 of the presentembodiment, the electric time constant is small because the inductanceof the stator 520 is reduced, and in a situation where the electricaltime constant is small, it is desirable to increase the switchingfrequency (carrier frequency) and increase the switching speed. In thisrespect, the charge supply capacitor 604 is connected in parallel to theseries connection body of the switches 601 and 602 of each phase, andthus the wiring inductance becomes low, and appropriate surgecountermeasures are possible even with a configuration in which theswitching speed is increased.

The high potential side terminal of the inverter 600 is connected to thepositive electrode terminal of a DC power supply 605, and the lowpotential side terminal is connected to the negative electrode terminal(ground) of the DC power supply 605. Further, a smoothing capacitor 606is connected to the high potential side terminal and the low potentialside terminal of the inverter 600, in parallel to the DC power supply605.

The switch module 532A has the respective switches 601 and 602(semiconductor switching elements), the drive circuit 603 (specifically,an electric element constituting the drive circuit 603), and the chargesupply capacitor 604, as heat-generating components. Further, thecapacitor module 532B has the smoothing capacitor 606 as aheat-generating component. A specific configuration example of theswitch module 532A is illustrated in FIG. 60.

As illustrated in FIG. 60, the switch module 532A has a module case 611as a housing case, and the switches 601 and 602 for one phase housed inthe module case 611, the drive circuit 603, and the charge supplycapacitor 604. The drive circuit 603 is configured as a dedicated IC ora circuit board and is provided in the switch module 532A.

The module case 611 is made of an insulating material such as resin, andis fixed to the outer peripheral wall WA1 with its side surface incontact with the inner peripheral surface of the inner wall member 542of the inverter unit 530. The module case 611 is filled with a moldingmaterial such as resin. In the module case 611, the switches 601 and 602and the drive circuit 603, and the switches 601 and 602 and thecapacitor 604 are electrically connected by a wiring 612, respectively.More specifically, the switch module 532A is attached to the outerperipheral wall WA1 via the spacer 549, but the spacer 549 is notillustrated.

In a state where the switch module 532A is fixed to the outer peripheralwall WA1, the side of the switch module 532A closer to the outerperipheral wall WA1, that is, the side closer to the cooling waterpassage 545 has higher cooling performance. Therefore, the order of thearrangement of the switches 601 and 602, the drive circuit 603, and thecapacitor 604 is determined in accordance with the cooling performance.Specifically, when comparing the amount of heat generated, the switches601 and 602, the capacitor 604, and the drive circuit 603 are in theorder from the largest, and therefore the switches 601 and 602, thecapacitor 604, and the drive circuit 603 are arranged in this order fromthe side closer to the outer peripheral wall WA1 in accordance with themagnitude order of the amount of heat generated. Moreover, the contactsurface of the switch module 532A is preferably smaller than thecontactable surface on the inner peripheral surface of the inner wallmember 542.

Furthermore, although detailed illustration of the capacitor module 5328is omitted, the capacitor module 532B is configured such that thecapacitor 606 is housed in a module case having the same shape and sizeas that of the switch module 532A. Similarly to the switch module 532A,the capacitor module 5328 is fixed to the outer peripheral wall WA1 in astate where the side surface of the module case 611 is in contact withthe inner peripheral surface of the inner wall member 542 of theinverter housing 531.

The switch module 532A and the capacitor module 532B do not necessarilyhave to be arranged concentrically on the radial inside of the outerperipheral wall WA1 of the inverter housing 531. For example, the switchmodule 532A may be arranged radially inside the capacitor module 532B,or vice versa.

When the rotating electric machine 500 is driven, heat exchange isperformed between the switch module 532A and the capacitor module 532Band the cooling water passage 545 via the inner wall member 542 of theouter peripheral wall WA1. As a result, the switch module 532A and thecapacitor module 532B are cooled.

Each electric module 532 may have a configuration in which cooling wateris drawn into the module and the cooling water is used to cool theinside of the module. Here, the water-cooled structure of the switchmodule 532A will be described with reference to FIGS. 61A and 61B. FIG.61A is a vertical cross-sectional view illustrating a cross-sectionalstructure of the switch module 532A in a direction crossing the outerperipheral wall WA1, and FIG. 61B is a cross-sectional view taken alonga line 61B-61B of FIG. 61A.

As illustrated in FIGS. 61A and 618, as is the case with FIG. 60, theswitch module 532A has the module case 611, the switches 601 and 602 forone phase, the drive circuit 603, and the capacitor 604, as in FIG. 60.In addition, the switch module 532A has a cooling device composed of apair of piping sections 621 and 622 and a cooler 623. In the coolingdevice, the pair of piping sections 621 and 622 are composed of aninflow side piping section 621 that allows cooling water to flow in fromthe cooling water passage 545 of the outer peripheral wall WA1 to thecooler 623 and an outflow side piping section 622 that allows coolingwater to flow out from the cooler 623 to the cooling water passage 545.The cooler 623 is provided in accordance with an object to be cooled,and a one-stage or multiple-stage cooler 623 is used in the coolingdevice. In the configurations of FIGS. 61A and 61B, two-stage coolers623 are provided in a direction away from the cooling water passage 545,that is, in the radial direction of the inverter unit 530, in a state ofbeing separated from each other, and cooling water is supplied to thoserespective coolers 623 via the pair of piping sections 621 and 622. Thecooler 623 has, for example, a hollow inside. However, an inner fin maybe provided inside the cooler 623.

In the configuration including the two-stage coolers 623, (1) the outerperipheral wall WA1 side of the first-stage cooler 623, (2) between thefirst-stage and second-stage coolers 623, and (3) the opposite-to-outerperipheral wall side of the second stage cooler 623 is the place wherethe electric components to be cooled are placed, and each of theseplaces is (2). (1), and (3) in order from the one with the highestcooling performance. That is, the place sandwiched between the twocoolers 623 has the highest cooling performance, and in the placeadjacent to any one of the coolers 623, the place closer to the outerperipheral wall WA1 (cooling water passage 545) has higher coolingperformance. Taking this into consideration, in the configurationsillustrated in FIGS. 61A and 61B, the switches 601 and 602 are arranged(2) between the first-stage and second-stage coolers 623, the condenser604 is arranged on (1) the outer peripheral wall WA1 side of thefirst-stage cooler 623, and the drive circuit 603 is arranged on (3) theopposite-to-outer peripheral wall side of the second-stage cooler 623.Moreover, although not illustrated, the drive circuit 603 and thecapacitor 604 may be arranged in reverse.

In either case, in the module case 611, the switches 601 and 602 and thedrive circuit 603, and the switches 601 and 602 and the capacitor 604are electrically connected by a wiring 612, respectively. Further, sincethe switches 601 and 602 are located between the drive circuit 603 andthe capacitor 604, the wiring 612 extending from the switches 601 and602 toward the drive circuit 603 and the wiring 612 extending from theswitches 601 and 602 toward the capacitor 604 are in a relation in whichthey extend in opposite directions.

As illustrated in FIG. 61B, the pair of piping sections 621 and 622 arearranged side by side in the circumferential direction, that is, on theupstream side and the downstream side of the cooling water passage 545,and cooling water flows into the cooler 623 from the inflow side pipingsection 621 located on the upstream side, and then the cooling waterflows out from the outflow side piping section 622 located on thedownstream side. Moreover, in order to promote the inflow of the coolingwater into the cooling device, the cooling water passage 545 ispreferably provided with a regulating section 624 that regulates theflow of cooling water, at a position between the inflow side pipingsection 621 and the outflow side piping section 621 when viewed in thecircumferential direction. The regulating section 624 may be a blockingsection that blocks the cooling water passage 545, or a throttle sectionthat reduces the passage area of the cooling water passage 545.

FIG. 62 illustrates another cooling structure of the switch module 532A.FIG. 62A is a vertical cross-sectional view illustrating across-sectional structure of the switch module 532A in a directioncrossing the outer peripheral wall WA1, and FIG. 62B is across-sectional view taken along a line 62B-62B of FIG. 62A.

The configurations of FIGS. 62A and 62B differ from the configurationsof FIGS. 61A and 61B described above in that the pair of piping sections621 and 622 in the cooling device are arranged differently, and a pairof piping sections 621 and 622 are arranged side by side in the axialdirection. Further, as illustrated in FIG. 62C, in the cooling waterpassage 545, the passage portion communicating with the inflow sidepiping section 621 and the passage portion communicating with theoutflow side piping section 622 are separated in the axial direction.Each of these passage portions is communicated with each other throughthe respective piping sections 621 and 622 and each cooler 623.

In addition, the following configuration can be used as the switchmodule 532A.

In the configuration illustrated in FIG. 63A, the cooler 623 is changedfrom two stages to one stage as compared with the configurationillustrated in FIG. 61A. In this case, the place where the coolingperformance is highest in the module case 611 is different from that inFIG. 61A, and the cooling performance is highest in the place on theouter peripheral wall WA1 side of both sides in the radial direction(both sides in the right-left direction in the figure) of the cooler623, and then the cooling performance is lowered in the order of theplace on the opposite-to-outer peripheral wall side of the cooler 623and the place away from the cooler 623. Taking this into consideration,in the configuration illustrated in FIG. 63A, the switches 601 and 602are arranged on the outer peripheral wall WA1 side of both sides in theradial direction (both sides in the right-left direction in the figure)of the cooler 623, the capacitor 604 is arranged on theopposite-to-outer peripheral wall side of the cooler 623, and the drivecircuit 603 is arranged in the place away from the cooler 623.

Further, in the switch module 532A, it is possible to change theconfiguration in which the switches 601 and 602 for one phase, the drivecircuit 603, and the capacitor 604 are housed in the module case 611.For example, the module case 611 may house either one of the switches601 and 602 for one phase and the drive circuit 603 and the capacitor604.

In FIG. 63B, the pair of piping sections 621 and 622 and the two-stagecoolers 623 are provided in the module case 611, the switches 601 and602 are arranged between the first-stage and second-stage coolers 623,and the capacitor 604 or the drive circuit 603 is arranged on the outerperipheral wall WA1 side of the first stage cooler 623. Further, it isalso possible to integrate the switches 601 and 602 and the drivecircuit 603 into a semiconductor module, and to house the semiconductormodule and the capacitor 604 in the module case 611.

Moreover, in FIG. 631, in the switch module 532A, a capacitor ispreferably arranged on the side opposite to the switches 601 and 602 inat least one of the coolers 623 arranged on both sides with the switches601 and 602 therebetween. That is, there may be a configuration in whichthe capacitor 604 is arranged only on one of the outer peripheral wallWA1 side of the first-stage cooler 623 and the opposite-to-peripheralwall side of the second-stage cooler 623, or a configuration in whichthe capacitor 604 is arranged on the both sides.

In the present embodiment, of the switch module 532A and the capacitormodule 532B, only the switch module 532A is configured to draw coolingwater from the cooling water passage 545 into the module. However, theconfiguration may be changed in such a manner that cooling water isdrawn into both modules 532A and 532B from the cooling water passage545.

Further, it is also possible to cool each electric module 532 bydirectly applying cooling water to the outer surface of each electricmodule 532. For example, as illustrated in FIG. 64, by embedding theelectric module 532 in the outer peripheral wall WA1, the cooling wateris applied to the outer surface of the electric module 532. In thiscase, it is conceivable to immerse a part of the electric module 532 inthe cooling water passage 545, or to expand the cooling water passage545 further in the radial direction than in the configurationillustrated in FIG. 58 or the like to immerse all the electric modules532 in the cooling water passage 545. In the case where the electricmodule 532 is immersed in the cooling water passage 545, the coolingperformance can be further improved by providing a fin in the modulecase 611 (the immersed portion of the module case 611) to be immersed.

Further, the electric module 532 includes a switch module 532A and acapacitor module 5323, and there is a difference in the amount of heatgenerated when both of them are compared. In consideration of thispoint, it is also possible to devise the arrangement of each electricmodule 532 in the inverter housing 531.

For example, as illustrated in FIG. 65, a plurality of switch modules532A are arranged in the circumferential direction without beingdispersed, and arranged on the upstream side of the cooling waterpassage 545, that is, on the side close to the inlet passage 571. Inthis case, the cooling water flowing in from the inlet passage 571 isfirst used for cooling the three switch modules 532A, and then used forcooling each capacitor module 532B. Moreover, in FIG. 65, the pair ofpiping sections 621 and 622 are arranged side by side in the axialdirection as in the preceding FIGS. 62A and 62B, but the presentinvention is not limited to this, and the pair of piping sections 621and 622 may be arranged side by side in the circumferential direction asin the preceding FIGS. 61A and 61B.

Next, the configuration related to the electrical connection in eachelectric module 532 and the bus bar module 533 will be described. FIG.66 is a cross-sectional view taken along a line 66-66 of FIG. 49, andFIG. 67 is a cross-sectional view taken along a line 67-67 of FIG. 49.FIG. 68 is a perspective view illustrating the busbar module 533 alone.Here, the configuration related to the electrical connection in eachelectric module 532 and the bus bar module 533 will be described withreference to each of these figures.

As illustrated in FIG. 66, in the inverter housing 531, at positionsadjacent to each other in the circumferential direction of theprotruding section 573 provided on the inner wall member 542 (that is,the protruding section 573 provided with the inlet passage 571 and theoutlet passage 572 communicating with the cooling water passage 545),three switch modules 532A are arranged side by side in thecircumferential direction, and next to them, six capacitor modules 5328are arranged side by side in the circumferential direction. As theoutline, in the inverter housing 531, the inside of the outer peripheralwall WA1 is equally divided into 10 regions (that is, the number ofmodules+1) in the circumferential direction, and one electric module 532is arranged in each of the nine regions, and the protruding section 573is provided in the remaining one region. The three switch modules 532Aare a U-phase module, a V-phase module, and a W-phase module.

As illustrated in FIG. 66 and the above-mentioned FIGS. 56 and 57, eachelectric module 532 (switch module 532A and capacitor module 5328) has aplurality of module terminals 615 extending from the module case 611.The module terminal 615 is a module input/output terminal for performingelectrical input/output in each electric module 532. The module terminal615 is provided so as to extend in the axial direction, and morespecifically, the module terminal 615 is provided so as to extend fromthe module case 611 toward the back side of the rotor carrier 511(outside the vehicle)(see FIG. 51).

The module terminals 615 of each electric module 532 are connected tothe bus bar module 533, respectively. The number of module terminals 615differs between the switch module 532A and the capacitor module 5328.The switch module 532A is provided with four module terminals 615, andthe capacitor module 532B is provided with two module terminals 615.

Further, as illustrated in FIG. 68, the bus bar module 533 has anannular section 631 forming an annular shape, three external connectionterminals 632 extending from the annular section 631 and enablingconnection with external devices such as a power supply device and anECU (electronic control unit), and a winding connection terminal 633connected to the winding end of each phase in the stator winding 521.The bus bar module 533 corresponds to a “terminal module”.

The annular section 631 is arranged in the inverter housing 531 at aposition on the radial inside of the outer peripheral wall WA1 and onone side in the axial direction of each electric module 532. The annularsection 631 has an annular main body formed of, for example, aninsulating member such as resin, and a plurality of bus bars embeddedtherein. The plurality of bus bars are connected to the module terminal615 of each electric module 532, each external connection terminal 632,and each phase winding of the stator winding 521. The details will bedescribed below.

The external connection terminal 632 is composed of a high potentialside power terminal 632A and a low potential side power terminal 632Bconnected to the power supply device, and one signal terminal 632Cconnected to an external ECU. Each of these external connectionterminals 632 (632A to 632C) is provided so as to be arranged in a linein the circumferential direction and to extend n the axial direction onthe radial inside of the annular section 631. As illustrated in FIG. 51,in a state where the bus bar module 533 is assembled to the inverterhousing 531 together with each electric module 532, one end of theexternal connection terminal 632 is configured to protrude from the endplate 547 of the boss forming member 543. Specifically, as illustratedin FIGS. 56 and 57, the end plate 547 of the boss forming member 543 isprovided with an insertion hole 547 a, a cylindrical grommet 635 isattached to the insertion hole 547 a, and the external connectionterminal 632 is provided with the grommet 635 inserted. The grommet 635also functions as a sealed connector.

The winding connection terminal 633 is a terminal connected to thewinding end of each phase of the stator winding 521, and is provided soas to extend radially outward from the annular section 631. The windingconnection terminal 633 has a winding connection terminal 633U connectedto the end of the U-phase winding in the stator winding 521, a windingconnection terminal 633V connected to the end of the V-phase winding,and a winding connection terminal 633W connected to each connection atthe end of the W-phase winding. It is preferable to provide a currentsensor 634 that detects the current (U-phase current, V-phase current,W-phase current) flowing through each of these winding connectionterminals 633 and each phase winding (see FIG. 70).

Moreover, the current sensor 634 may be arranged outside the electricmodule 532 and around each winding connection terminal 633, or may bearranged inside the electric module 532.

Here, the connection between each electric module 532 and the bus barmodule 533 will be described more specifically with reference to FIGS.69 and 70. FIG. 69 is a diagram illustrating each electric module 532developed in a plane and schematically illustrating an electricalconnection state between each electric module 532 and the bus bar module533. FIG. 70 is a diagram schematically illustrating the connectionbetween each electric module 532 and the bus bar module 533 in a statewhere each electric module 532 is arranged in an annular shape.Moreover, in FIG. 69, the path for power transmission is illustrated bya solid line, and the path of the signal transmission system isillustrated by a dashed line. FIG. 70 illustrates only the path forpower transmission.

The bus bar module 533 has a first bus bar 641, a second bus bar 642,and a third bus bar 643 as bus bars for power transmission. Of these,the first bus bar 641 is connected to the high potential side powerterminal 632A, and the second bus bar 642 is connected to the lowpotential side power terminal 632B. Further, three third bus bars 643are connected to the U-phase winding connection terminal 633U, theV-phase winding connection terminal 633V, and the W-phase windingconnection terminal 633W, respectively.

Further, the winding connection terminal 633 and the third bus bar 643are portions that easily generate heat due to the operation of therotating electric machine 10. Therefore, a terminal block (notillustrated) may be interposed between the winding connection terminal633 and the third bus bar 643, and the terminal block may be broughtinto contact with the inverter housing 531 having the cooling waterpassage 545. Alternatively, the winding connection terminal 633 or thethird bus bar 643 may be bent into a crank shape to bring the windingconnection terminal 633 or the third bus bar 643 into contact with theinverter housing 531 having the cooling water passage 545.

With such a configuration, the heat generated at the winding connectionterminal 633 and the third bus bar 643 can be dissipated to the coolingwater in the cooling water passage 545.

Moreover, in FIG. 70, the first bus bar 641 and the second bus bar 642are illustrated as bus bars having an annular shape, but each of thesebus bars 641 and 642 does not necessarily have to be connected in anannular shape and may have a substantially C-shape with a partdiscontinuous in the circumferential direction. Further, each windingconnection terminal 633U, 633V, and 633W may be individually connectedto the switch module 532A corresponding to each phase, and therefore maybe directly connected to each switch module 532A (actually, the moduleterminal 615) without going through the bus bar module 533.

Meanwhile, each switch module 532A has four module terminals 615composed of a positive electrode side terminal, a negative electrodeside terminal, a winding terminal, and a signal terminal. Of these, thepositive electrode side terminal is connected to the first bus bar 641,the negative electrode side terminal is connected to the second bus bar642, and the winding terminal is connected to the third bus bar 643.

Further, the bus bar module 533 has a fourth bus bar 644 as a bus bar ofthe signal transmission system. The signal terminal of each switchmodule 532A is connected to the fourth bus bar 644, and the fourth busbar 644 is connected to the signal terminal 632C.

In the present embodiment, the control signal for each switch module532A is input from the external ECU via the signal terminal 632C. Thatis, the respective switches 601 and 602 in each switch module 532A areturned on/off by a control signal input via the signal terminal 632C.Therefore, each switch module 532A is connected to the signal terminal632C without going through a control device disposed in the rotatingelectric machine on the way. However, it is also possible to change thisconfiguration in such a manner that a rotating electric machine has abuilt-in control device and the control signal from the control deviceis input to each switch module 532A. Such a configuration is illustratedin FIG. 71.

In the configuration of FIG. 71, a control board 651 on which a controldevice 652 is mounted is provided, and the control device 652 isconnected to each switch module 532A. Further, the signal terminal 632Cis connected to the control device 652. In this case, the control device652 inputs a command signal related to power running or power generationfrom, for example, an external ECU which is a higher-level controldevice, and appropriately turns on/off the switches 601 and 602 of eachswitch module 532A on the basis of the command signal.

In the inverter unit 530, the control board 651 is preferably arrangedon the further outside of the vehicle than the bus bar module 533 (backside of the rotor carrier 511). Alternatively, the control board 651 maybe arranged between each electric module 532 and the end plate 547 ofthe boss forming member 543. The control board 651 is preferablyarranged in such a manner that at least a part thereof overlaps witheach electric module 532 in the axial direction.

Further, each capacitor module 532B has two module terminals 615composed of a positive electrode side terminal and a negative electrodeside terminal, the positive electrode side terminal is connected to thefirst bus bar 641, and the negative electrode side terminal is connectedto the second bus bar 642.

As illustrated in FIGS. 49 and 50, the protruding section 573 having theinlet passage 571 and the outlet passage 572 for cooling water isprovided in the inverter housing 531 at a position aligned with eachelectric module 532 in the circumferential direction, and the externalconnection terminals 632 is provided so as to be adjacent to theprotruding section 573 in the radial direction. In other words, theprotruding section 573 and the external connection terminal 632 areprovided at the same angular position in the circumferential direction.In the present embodiment, the external connection terminal 632 isprovided at a position on the radial inside of the protruding section573. Further, when viewed from the inside of the vehicle of the inverterhousing 531, the end plate 547 of the boss forming member 543 isprovided with the water channel port 574 and the external connectionterminal 632 arranged side by side in the radial direction (see FIG.48).

In this case, by arranging the protruding section 573 and the externalconnection terminal 632 side by side in the circumferential directiontogether with the plurality of electric modules 532, the inverter unit530 can be downsized, and thus the rotating electric machine 500 can bedownsized.

Referring to FIGS. 45 and 47 illustrating the structure of the wheel400, the cooling pipe H2 is connected to the water channel port 574, theelectric wiring H1 is connected to the external connection terminal 632,and in that state, the electric wiring H1 and the cooling pipe H2 arehoused in the housing duct 440.

Moreover, in the above configuration, the three switch modules 532A arearranged side by side in the circumferential direction next to theexternal connection terminal 632 in the inverter housing 531, and nextto them, the six capacitor modules 532B are arranged side by side in thecircumferential direction. However, this may be changed. For example,the three switch modules 532A may be arranged side by side at a positionfarthest from the external connection terminal 632, that is, a positionopposite to the external connection terminal 632 with the rotating shaft501 therebetween. Further, it is also possible to disperse each switchmodule 532A in such a manner that the capacitor modules 532B arearranged on both sides of each switch module 532A.

If each switch module 532A is arranged at the position farthest from theexternal connection terminal 632, that is, a position opposite to theexternal connection terminal 632 with the rotating shaft 501therebetween, a malfunction or the like caused by mutual inductancebetween the external connection terminal 632 and each switch module 532Acan be suppressed.

Next, the configuration of a resolver 660 provided as a rotation anglesensor will be described.

As illustrated in FIGS. 49 to 51, the inverter housing 531 is providedwith a resolver 660 that detects the electrical angle θ of the rotatingelectric machine 500. The resolver 660 is an electromagnetic inductiontype sensor, and includes a resolver rotor 661 fixed to the rotatingshaft 501 and a resolver stator 662 arranged so as to face the radialoutside of the resolver rotor 661. The resolver rotor 661 has a discring shape, and is provided coaxially with the rotating shaft 501 withthe rotating shaft 501 inserted. The resolver stator 662 includes anannular stator core 663 and a stator coil 664 wound around a pluralityof teeth formed on the stator core 663. The stator coil 664 includes aone-phase excitation coil and a two-phase output coil.

The exciting coil of the stator coil 664 is excited by a sinusoidalexcitation signal, and the magnetic flux generated in the exciting coilby the excitation signal interlinks a pair of output coils. In doing so,since the relative arrangement relation between the exciting coil andthe pair of output coils changes periodically in accordance with therotation angle of the resolver rotor 661 (that is, the rotation angle ofthe rotation shaft 501), the amount of magnetic flux interlinking thepair of output coils changes periodically. In the present embodiment,the pair of output coils and the exciting coil are arranged in such amanner that the phases of the voltages generated in the pair of outputcoils are shifted by π/2 from each other. As a result, the outputvoltage of each of the pair of output coils becomes a modulated wave inwhich the excitation signal is modulated by the modulated waves sin θand cos θ, respectively. More specifically, when the excitation signalis “sin Ωt”, the modulated waves are “sin θ*sin Ωt” and “cos θ *sin Ωt”,respectively.

The resolver 660 has a resolver digital converter. The resolver digitalconverter calculates the electrical angle θ by detection based on thegenerated modulated wave and the excitation signal. For example, theresolver 660 is connected to the signal terminal 632C, and thecalculation result of the resolver digital converter is output to anexternal device via the signal terminal 632C. Further, in a case wherethe rotating electric machine 500 has a built-in control device, thecalculation result of the resolver digital converter is input to thecontrol device.

Here, the assembly structure of the resolver 660 in the inverter housing531 will be described.

As illustrated in FIGS. 49 and 51, the boss section 548 of the bossforming member 543 constituting the inverter housing 531 has a hollowtubular shape, and on the inner peripheral side of the boss section 548,a protruding portion 548 a extending in a direction orthogonal to theaxial direction is formed. Then, the resolver stator 662 is fixed by ascrew or the like in a state of being in contact with the protrudingsection 548 a in the axial direction. In the boss section 548, thebearing 560 is provided on one side in the axial direction with theprotruding section 548 a therebetween, and the resolver 660 is coaxiallyprovided on the other side.

Further, in the hollow portion of the boss section 548, a protrudingsection 548 a is provided on one side of the resolver 660 in the axialdirection, and a disc ring-shaped housing cover 666 that closes thehousing space of the resolver 660 is attached on the other side. Thehousing cover 666 is made of a conductive material such as carbon fiberreinforced plastic (CFRP). A hole 666 a through which the rotating shaft501 is inserted is formed in the central portion of the housing cover666. In the hole 666 a, a sealing material 667 that seals the airspacetherebetween with the outer peripheral surface of the rotating shaft501. The resolver housing space is sealed by the sealing material 667.The sealing material 667 is preferably, for example, a sliding seal madeof a resin material.

The space in which the resolver 660 is housed is a space surrounded bythe boss section 548 forming an annular shape in the boss forming member543 and sandwiched between the bearing 560 and the housing cover 666 inthe axial direction, and the circumference of the resolver 660 issurrounded by a conductive material. This makes it possible to suppressthe influence of electromagnetic noise on the resolver 660.

Further, as described above, the inverter housing 531 has the outerperipheral wall WA1 and the inner peripheral wall WA2 that together forma double wall (see FIG. 57), the stator 520 is arranged on the outsideof the double peripheral walls (outside the outer peripheral wall WA1),the electric module 532 is arranged between the double peripheral walls(between WA1 and WA2), and the resolver 660 is arranged inside thedouble peripheral walls (inside the inner peripheral wall WA2). Sincethe inverter housing 531 is a conductive member, the stator 520 and theresolver 660 are arranged so as to be separated from each other by aconductive partition wall (particularly a double conductive partitionwall in the present embodiment), and the occurrence of mutual magneticinterference between the stator 520 side (magnetic circuit side) and theresolver 660 can be suitably suppressed.

Next, the rotor cover 670 provided on the open end side of the rotorcarrier 511 will be described.

As illustrated in FIGS. 49 and 51, one side of the rotor carrier 511 inthe axial direction is open, and the substantially disc ring-shapedrotor cover 670 is attached to the open end. The rotor cover 670 ispreferably fixed to the rotor carrier 511 by any joining method such aswelding, adhesion, or screwing. It is more preferable that the rotorcover 670 has a portion whose dimension is set smaller than the innercircumference of the rotor carrier 511 in such a manner that themovement of the magnet unit 512 in the axial direction can besuppressed. The outer diameter dimension of the rotor cover 670 matchesthe outer diameter dimension of the rotor carrier 511, and the innerdiameter dimension of the rotor cover 670 is slightly larger than theouter diameter dimension of the inverter housing 531. The outer diameterdimension of the inverter housing 531 and the inner diameter dimensionof the stator 520 are the same.

As described above, the stator 520 is fixed to the radial outside of theinverter housing 531. At the joint portion where the stator 520 and theinverter housing 531 are joined to each other, the inverter housing 531protrudes axially with respect to the stator 520. In addition, the rotorcover 670 is attached so as to surround the protruding portion of theinverter housing 531. In this case, a sealing material 671 that sealsthe gap between the end face of the rotor cover 670 on the innerperipheral side and the outer peripheral surface of the inverter housing531 is provided. The housing space of the magnet unit 512 and the stator520 is sealed by the sealing material 671. The sealing material 671 ispreferably, for example, a sliding seal made of a resin material.

According to the present embodiment described in detail above, thefollowing excellent effects can be obtained.

In the rotating electric machine 500, the outer peripheral wall WA1 ofthe inverter housing 531 is arranged radially inside the magneticcircuit section composed of the magnet unit 512 and the stator winding521, and the cooling water passage 545 is formed on the outer peripheralwall WA1. Further, a plurality of electric modules 532 are arranged inthe circumferential direction along the outer peripheral wall WA1, onthe radial inside of the outer peripheral wall WA1. As a result, themagnetic circuit section, the cooling water passage 545, and the powerconverter can be arranged so as to be stacked in the radial direction ofthe rotating electric machine 500, and an efficient componentarrangement is possible while reducing the dimensions in the axialdirection. Further, the plurality of electric modules 532 constitutingthe power converter can be efficiently cooled. As a result, the highefficiency and downsizing of the rotating electric machine 500 can beachieved.

The electric module 532 (switch module 532A, capacitor module 532B)having heat-generating components such as a semiconductor switchingelement and a capacitor is provided in contact with the inner peripheralsurface of the outer peripheral wall WA1. As a result, the heat in eachelectric module 532 is transferred to the outer peripheral wall WA1, andthe electric module 532 is suitably cooled by the heat exchange in theouter peripheral wall WA1.

In the switch module 532A, the coolers 623 are arranged on both sides ofthe switches 601 and 602, respectively, and in at least one of thecoolers 623 on both sides of the switches 601 and 602, the capacitor 604is arranged on the side opposite to the switches 601 and 602. As aresult, the cooling performance for the switches 601 and 602 can beimproved, and the cooling performance of the capacitor 604 can also beimproved.

In the switch module 532A, the coolers 623 are arranged on both sides ofthe switches 601 and 602, respectively, and in one of the coolers 623 onboth sides of the switches 601 and 602, the drive circuit 603 isarranged on the side opposite to the switches 601 and 602, and in theother of the coolers 623, the capacitor 604 is arranged on the sideopposite to the switches 601 and 602. As a result, the coolingperformance for the switches 601 and 602 can be improved, and thecooling performance of the drive circuit 603 and the capacitor 604 canalso be improved.

For example, in the switch module 532A, cooling water flows into themodule from the cooling water passage 545, and the semiconductorswitching element or the like is cooled by the cooling water. In thiscase, the switch module 532A is cooled by heat exchange by the coolingwater inside the module in addition to heat exchange by the coolingwater on the outer peripheral wall WA1. As a result, the cooling effectof the switch module 532A can be enhanced.

In the cooling system in which the cooling water flows into the coolingwater passage 545 from the external circulation path 575, the switchmodule 532A is arranged on the upstream side near the inlet passage 571of the cooling water passage 545, and the capacitor module 532B isarranged on the downstream side of the switch module 532A. In this case,assuming that the cooling water flowing through the cooling waterpassage 545 is lower in temperature toward the upstream side, it ispossible to implement a configuration in which the switch module 532A ispreferentially cooled.

The interval between the electric modules adjacent to each other in thecircumferential direction is partially widened, and the protrudingsection 573 having the inlet passage 571 and the outlet passage 572 isprovided in the portion where the interval is widened (second intervalINT2). As a result, the inlet passage 571 and the outlet passage 572 ofthe cooling water passage 545 can be suitably formed in the portion thatis radially inside of the outer peripheral wall WA1. That is, in orderto improve the cooling performance, it is necessary to secure the flowamount of the refrigerant, and for that purpose, it is conceivable toincrease the opening areas of the inlet passage 571 and the outletpassage 572. In this regard, as described above, by partially wideningthe interval between the electric modules and providing the protrudingsection 573, the inlet passage 571 and the outlet passage 572 having adesired size can be suitably formed.

The external connection terminal 632 of the bus bar module 533 isarranged at a position radially aligned with the protruding section 573on the radial inside of the outer peripheral wall WA1. That is, theexternal connection terminal 632 is arranged together with theprotruding section 573 in the portion where the interval between theelectric modules adjacent to each other in the circumferential directionis widened (the portion corresponding to the second interval INT2). As aresult, the external connection terminal 632 can be suitably arrangedwhile avoiding interference with each electric module 532.

In the outer rotor type rotating electric machine 500, the stator 520 isfixed to the radial outside of the outer peripheral wall WA1, and aplurality of electric modules 532 are arranged on the radial inside. Asa result, the heat of the stator 520 is transferred to the outerperipheral wall WA) from the radial outside, and the heat of theelectric module 532 is transferred from the radial inside. In this case,the stator 520 and the electric module 532 can be cooled at the sametime by the cooling water flowing the cooling water passage 545, and theheat of the heat-generating member in the rotating electric machine 500can be efficiently released.

The electric module 532 on the radial inside and the stator winding 521on the radial outside are electrically connected by the windingconnection terminal 633 of the bus bar module 533 with the outerperipheral wall WA1 therebetween. Further, in this case, the windingconnection terminal 633 is provided at a position axially separated fromthe cooling water passage 545. As a result, even in a configuration inwhich the cooling water passage 545 is formed in an annular shape on theouter peripheral wall WA1, that is, the inside and outside of the outerperipheral wall WA1 are separated by the cooling water passage 545, theelectric module 532 and the stator winding 521 can be suitablyconnected.

In the rotating electric machine 500 of the present embodiment, byreducing or eliminating the teeth (iron core) between the respectiveconductors 523 arranged in the circumferential direction in the stator520, the torque limitation caused by the magnetic saturation between therespective conductors 523 is suppressed, and the torque decrease issuppressed by making the conductor 523 flat and thin. In this case, evenif the outer diameter dimension of the rotating electric machine 500 isthe same, the region on the radial inside of the magnetic circuitsection can be expanded by reducing the thickness of the stator 520, andwith the use of the inner region, the outer peripheral wall WA1 havingthe cooling water passage 545 and the plurality of electric modules 532provided radially inside the outer peripheral wall WA1 can be suitablyarranged.

In the rotating electric machine 500 of the present embodiment, themagnet magnetic flux in the magnet unit 512 is collected on the d-axisside, and thus the magnet magnetic flux on the d-axis is strengthened,and the torque can be increased accordingly. In this case, as the radialthickness dimension can be reduced (thinned) in the magnet unit 512, theregion on the radial inside of the magnetic circuit section can beexpanded by reducing the thickness of the stator 520, and with the useof the inner region, the outer peripheral wall WA1 having the coolingwater passage 545 and the plurality of electric modules 532 providedradially inside the outer peripheral wall WA1 can be suitably arranged.

Further, not only the magnetic circuit section, the outer peripheralwall WA1, and the plurality of electric modules 532, but also thebearing 560 and the resolver 660 can be suitably arranged in the radialdirection in the same manner.

The wheel 400 using the rotating electric machine 500 as an in-wheelmotor is mounted on a vehicle body via the base plate 405 fixed to theinverter housing 531 and a mounting mechanism such as a suspensiondevice. Here, since the rotating electric machine 500 has beendownsized, it is possible to save space even if it is assumed to beassembled to a vehicle body.

Therefore, it is possible to implement an advantageous configuration inexpanding the installation region of the power supply device such as abattery in the vehicle and expanding the vehicle interior space.

A modification on an in-wheel motor will be described below.

(First Modification in an In-Wheel Motor)

In the rotating electric machine 500, the electric module 532 and thebus bar module 533 are arranged radially inside the outer peripheralwall WA1 of the inverter unit 530, and the electric module 532 and thebus bar module 533 and the stator 520 are arranged radially inside andoutside so as to be separated from each other by the outer peripheralwall WA1, respectively. In such a configuration, the position of the busbar module 533 with respect to the electric module 532 can bearbitrarily set. Further, when connecting each phase winding of thestator winding 521 and the bus bar module 533 across the outerperipheral wall WA1 in the radial direction, a winding connection wire(for example, the winding connection terminal 633) used for theconnection can be arbitrarily set.

That is, as the position of the bus bar module 533 with respect to theelectric module 532, a configuration (α1) in which the bus bar module533 is located further outside of the vehicle in the axial directionthan the electric module 532, that is, on the back side in the rotorcarrier 511 side and a configuration (α2) in which the bus bar module533 is located further inside of the vehicle in the axial direction thanthe electric module 532, that is, on the front side in the rotor carrier511 side are conceivable.

Further, as a position to guide the winding connection windingconnection wire, a configuration (β1) in which the winding connectionwire is guided in the axial direction on the outside of the vehicle,that is, on the back side in the rotor carrier 511 side and aconfiguration (β2) in which the winding connection wire is guided in theaxial direction on the inside of the vehicle, that is, on the front sidein the rotor carrier 511 side are conceivable.

Hereinafter, four configuration examples relating to the arrangement ofthe electric module 532, the bus bar module 533, and the windingconnection wire will be described with reference to FIGS. 72A to 72D.FIGS. 72A to 72D are vertical cross-sectional views illustrating asimplified configuration of the rotating electric machine 500, in whichthe same reference signs are given to the configurations alreadydescribed. The winding connection wire 637 is an electric wiring thatconnects each phase winding of the stator winding 521 and the bus barmodule 533, and for example, the winding connection terminal 633described above corresponds to this.

In the configuration of FIG. 72A, the above (α1) is adopted as theposition of the bus bar module 533 with respect to the electric module532, and the above (β1) is adopted as the position for guiding thewinding connection wire 637. That is, the electric module 532, the busbar module 533, the stator winding 521, and the bus bar module 533 areall connected on the outside of the vehicle (the back side of the rotorcarrier 511). This corresponds to the configuration illustrated in FIG.49.

According to this configuration, the cooling water passage 545 can beprovided on the outer peripheral wall WA1 without fear of interferencewith the winding connection wire 637. Further, the winding connectionwire 637 that connects the stator winding 521 and the bus bar module 533can be easily achieved.

In the configuration of FIG. 72B, the above (α1) is adopted as theposition of the bus bar module 533 with respect to the electric module532, and the above (β2) is adopted as the position for guiding thewinding connection wire 637. That is, the electric module 532 and thebus bar module 533 are connected on the outside of the vehicle (the backside of the rotor carrier 511), and the stator winding 521 and the busbar module 533 are connected on the inside of the vehicle (the frontside of the rotor carrier 511).

According to this configuration, the cooling water passage 545 can beprovided on the outer peripheral wall WA1 without fear of interferencewith the winding connection wire 637.

In the configuration of FIG. 72C, the above (α2) is adopted as theposition of the bus bar module 533 with respect to the electric module532, and the above (β1) is adopted as the position for guiding thewinding connection wire 637. That is, the electric module 532 and thebus bar module 533 are connected on the inside of the vehicle (the frontside of the rotor carrier 511), and the stator winding 521 and the busbar module 533 are connected on the outside of the vehicle (the backside of the rotor carrier 511).

In the configuration of FIG. 72D, the above (α2) is adopted as theposition of the bus bar module 533 with respect to the electric module532, and the above (β2) is adopted as the position for guiding thewinding connection wire 637. That is, the electric module 532, the busbar module 533, the stator winding 521, and the bus bar module 533 areall connected on the inside of the vehicle (the front side of the rotorcarrier 511).

According to the configurations of FIGS. 72C and 72D, the bus bar module533 is arranged inside the vehicle (on the front side of the rotorcarrier 511), and thus it is considered the wiring becomes easy whenadding an electric component such as a fan motor. Further, it ispossible that the bus bar module 533 can be brought closer to theresolver 660 arranged further inside the vehicle than the bearing, andit is considered that wiring to the resolver 660 becomes easier.

(Second Modification in an In-Wheel Motor)

A modification of the mounting structure of the resolver rotor 661 willbe described below. That is, the rotating shaft 501, the rotor carrier511, and the inner ring 561 of the bearing 560 are a rotating body thatrotates integrally, and a modification of the mounting structure of theresolver rotor 661 with respect to the rotating body will be describedbelow.

FIGS. 73A to 73C are block diagrams illustrating an example of amounting structure of the resolver rotor 661 to the rotating body. Inany of the configurations, the resolver 660 is provided in a closedspace surrounded by the rotor carrier 511, the inverter housing 531 andthe like, and protected from external water, mud, and the like. Of FIGS.73A to 73C, in FIG. 73A, the bearing 560 has the same configuration asthat in FIG. 49. Further, in FIGS. 73B and 73C, the bearing 560 has aconfiguration different from that of FIG. 49, and is arranged at aposition away from the end plate 514 of the rotor carrier 511. In eachof these figures, two locations are illustrated as mounting locationsfor the resolver rotor 661. Moreover, although the resolver stator 662is not illustrated, for example, the boss section 548 of the bossforming member 543 should be extended to the outer peripheral side ofthe resolver rotor 661 or its vicinity, and the resolver stator 662should be fixed to the boss section 548.

In the configuration of FIG. 73A, the resolver rotor 661 is attached tothe inner ring 561 of the bearing 560. Specifically, the resolver rotor661 is provided on the axial end face of the flange 561 b of the innerring 561, or is provided on the axial end face of the tubular section561 a of the inner ring 561.

In the configuration of FIG. 73B, the resolver rotor 661 is attached tothe rotor carrier 511.

Specifically, the resolver rotor 661 is provided on the inner surface ofthe end plate 514 in the rotor carrier 511. Alternatively, in aconfiguration in which the rotor carrier 511 has a tubular section 515extending from the inner peripheral edge portion of the end plate 514along the rotating shaft 501, the resolver rotor 661 is provided on theouter peripheral surface of the tubular section 515 of the rotor carrier511. In the latter case, the resolver rotor 661 is arranged between theend plate 514 of the rotor carrier 511 and the bearing 560.

In the configuration of FIG. 73C, the resolver rotor 661 is attached tothe rotating shaft 501. Specifically, on the rotating shaft 501, theresolver rotor 661 is provided between the end plate 514 of the rotorcarrier 511 and the bearing 560. Alternatively, on the rotating shaft501, the resolver rotor 661 is arranged on the side opposite to therotor carrier 511 with the bearing 560 therebetween.

(Third Modification in an In-Wheel Motor)

A modification of the inverter housing 531 and the rotor cover 670 willbe described below with reference to FIG. 74. FIGS. 74A and 74B arevertical cross-sectional views illustrating a simplified configurationof the rotating electric machine 500, in which the same reference signsare given to the configurations already described. Moreover, theconfiguration illustrated in FIG. 74A substantially corresponds to theconfiguration described with reference to FIG. 49 and the like, and theconfiguration illustrated in FIG. 74B corresponds to the configurationin which a part of the configuration of FIG. 74A is modified.

In the configuration illustrated in FIG. 74A, the rotor cover 670 fixedto the open end of the rotor carrier 511 is provided so as to surroundthe outer peripheral wall WA1 of the inverter housing 531. That is, theend face on the inner diameter side of the rotor cover 670 faces theouter peripheral surface of the outer peripheral wall WA1, and thesealing material 671 is provided between them. Further, the housingcover 666 is attached to the hollow portion of the boss section 548 ofthe inverter housing 531, and the sealing material 667 is providedbetween the housing cover 666 and the rotating shaft 501. The externalconnection terminal 632 constituting the bus bar module 533 penetratesthe inverter housing 531 and extends to the inside of the vehicle (lowerside in the figure).

Further, in the inverter housing 531, the inlet passage 571 and theoutlet passage 572 communicating with the cooling water passage 545 areformed, and the water channel port 574 including the passage ends of theinlet passage 571 and the outlet passage 572 is formed.

On the other hand, in the configuration illustrated in FIG. 74B, theinverter housing 531 (specifically, the boss forming member 543) isformed with an annular protrusion 681 extending toward the protrudingside (inside the vehicle) of the rotating shaft 501. The rotor cover 670is provided so as to surround the protrusion 681 of the inverter housing531. That is, the end face on the inner diameter side of the rotor cover670 faces the outer peripheral surface of the protrusion 681, and thesealing material 671 is provided between them. Further, the externalconnection terminal 632 constituting the bus bar module 533 penetratesthe boss section 548 of the inverter housing 531 and extends into thehollow region of the boss section 548, and also penetrates the housingcover 666 and extends to the inside of the vehicle (lower side of thefigure).

Further, the inverter housing 531 is formed with the inlet passage 571and the outlet passage 572 communicating with the cooling water passage545, those inlet passage 571 and outlet passage 572 extend into thehollow region of the boss section 548 and extend to the further insideof the vehicle (lower side of the figure) than the housing cover 666 viaa relay pipe 682. In this configuration, the piping portion extendingfrom the housing cover 666 to the inside of the vehicle is the waterchannel port 574.

According to the configurations of FIGS. 74A and 748, the rotor carrier511 and the rotor cover 670 can be suitably rotated with respect to thehousing 531 while maintaining airtightness of the internal space of therotor carrier 511 and the rotor cover 670.

Moreover, in particular, according to the configuration of FIG. 748, theinner diameter of the rotor cover 670 is smaller than that of theconfiguration of FIG. 74A. Therefore, the inverter housing 531 and therotor cover 670 can be provided double in the axial direction at aposition further inside the vehicle than the electric module 532, andthe inconvenience caused by electromagnetic noise, which is a concern inthe electric module 532, is suppressed. Further, by reducing the innerdiameter of the rotor cover 670, the sliding diameter of the sealingmaterial 671 can be reduced, and mechanical loss in the rotating slidingportion can be suppressed.

(Fourth Modification in an In-Wheel Motor)

A modification of the stator winding 521 will be described below. FIG.75 illustrates a modification on the stator winding 521.

As illustrated in FIG. 75, in the stator winding 521, a conductormaterial having a rectangular cross section is used, and is wound by awave winding with the long side of the conductor material extending inthe circumferential direction. In this case, the conductors 523 of eachphase on the coil side of the stator winding 521 are arranged atpredetermined pitch intervals for each phase and are connected to eachother at the coil ends. The conductors 523 adjacent to each other in thecircumferential direction on the coil side are in contact with eachother at the end faces in the circumferential direction, or are arrangedclose to each other at a minute interval.

Further, in the stator winding 521, the conductor material is bent inthe radial direction for each phase at the coil end. More specifically,the stator winding 521 (conductor material) is bent inward in the radialdirection at a different position for each phase in the axial direction,whereby interference with each other in the respective U-phase, V-phase,and W-phase windings is avoided. In the illustrated configuration, theconductors are bent at a right angle inward in the radial direction foreach phase, with each phase winding being different by the thickness ofthe conductor material. In each of the conductors 523 arranged in thecircumferential direction, the length dimension between both ends in theaxial direction is preferably the same for each of the conductors 523.

Moreover, in a case where the stator core 522 is assembled to the statorwinding 521 to manufacture the stator 520, a part of the annular shapeof the stator winding 521 is preferably opened as a non-connection part(that is, the stator winding 521 is preferably made to be substantiallyC-shaped), and after assembling the stator core 522 on the innerperipheral side of the stator winding 521, the disconnecting portionsare preferably connected to each other to form the stator winding 521 inan annular shape.

In addition to the above, it is also possible to divide the stator core522 into a plurality of parts (for example, three or more) in thecircumferential direction, and assemble the core pieces divided into aplurality of pieces onto the inner peripheral side of the stator winding521 formed in an annular shape.

(Fifteenth Modification)

Hereinafter, a manufacturing method of the stator in the above-describedslotless outer rotor type rotating electric machine will be described.According to the stator of the present embodiment, interphase insulationis provided using three insulation sheets. FIG. 76 is a process flow(process diagram) showing a part of the manufacturing process of thestator according to the present embodiment. In this flow, as is known, atriangle symbol indicates a work or a component, and a circle symbolindicates processes such as an assembly or a machining.

At step S20, as shown in FIG. 77A, a recess 710 is formed at the sameinterval on a first insulation sheet 700 as an insulation paper. Then, alongitudinal shaped U-phase (first phase) conductor 800U of which thecross section is rectangular in shape is placed on each recess 710.Thus, a first assembly 810 is produced in which U-phase conductors 800Uare arranged at the same intervals on a first surface 701 of the firstinsulation sheet 701. In addition to the U-phase conductor 800U, V-phaseconductor 800V and W-phase conductor 800W which will be described laterconstitute a coil side. Note that the first insulation sheet 700 has arectangular shape in which the length dimension in the short-sidedirection is substantially the same as the length dimension of theU-phase conductor 800U. Further, at step S20, the U-phase conductor 800Uand the first insulation sheet 700 may be fixed by a fixing means suchas adhesive.

As shown in FIG. 77B, at step S21, a recess 730 is formed at the sameinterval on the second insulation sheet 720 as an insulation sheet.Then, a longitudinal shaped W-phase (third phase) conductor 800W ofwhich the cross section is rectangular in shape is placed on each recess730. Thus, a second assembly 820 is produced in which W-phase conductors800W are arranged at the same intervals on a first surface 721 of thesecond insulation sheet 720. According to the present embodiment, thenumber of W-phase conductors 800W used for step S21 is the same as thatof the U-phase conductors 800U. Also, the shape of the W-phase conductor800W is the same as that of the U-phase conductor 800U. According to thepresent embodiment, the shape of the second insulation sheet 720 is thesame as that of the first insulation sheet 700. At step S21, the W-phaseconductor 800W and the second insulation sheet 720 may be fixed by afixing means such as adhesive.

In the present embodiment, the first assembly 810 produced at step S20has the same configuration as that of the second assembly produced atstep S21. Hence, it is not necessary to divide the manufacturing processinto two steps, and two assemblies having the same configuration areproduced at a single step, whereby first and second assemblies 810 and820 may be produced. Thus, the manufacturing processes can besimplified.

At step S22, as shown in FIG. 78A, a V-phase (second phase) conductor800V of which the cross section is rectangular shape is disposed on thesecond surface 702 of the first insulation sheet 700 that constitutesthe first assembly 810 to be positioned adjacently to the U-phaseconductor 800U via the first insulation sheet 700. Thus, the V-phaseconductor 800V is disposed between adjacently positioned recesses 720 inthe first assembly 810. According to the present embodiment, the numberof V-phase conductors 800V used for step S22 is the same as that of theU-phase conductors 800U. Also, the shape of the V-phase conductor 800Vis the same as that of the U-phase conductor 800U.

At step S23, as shown in FIG. 78B, the first assembly 810 in which theV-phase conductor 800V is disposed and the second assembly 820 arelaminated such that the second surface 702 of the first insulation sheet700 that constitutes the first assembly 810 faces the second surface 722of the second insulation sheet 720 that constitutes the second assembly820. Thus, the V-phase conductor 800V is disposed at a portion adjacentto the W-phase conductor 800W via the second insulation sheet 720. Also,an interval between adjacently positioned U, V phase conductors 800U and800V in the circumferential direction, an interval between adjacentlypositioned V, W phase conductors in the circumferential direction and aninterval between adjacently positioned W, U phase conductors 800W and800U in the circumferential direction are the same.

Further, at step S23, a third insulation sheet 740 as an insulationpaper is made to come into contact with the first surface 701 of thefirst insulation sheet 700 and the U-phase conductor 800U. Thus, alaminate body of the first assembly 810, the second assembly 820 and thesecond insulation sheet 720, that is, a flat strip-shaped winding isproduced. The third insulation sheet 740 has a rectangular shape inwhich the length dimension in the short-side direction is substantiallythe same as the length dimension of the respective conductors 800U, 800Vand 800W.

At step S24, the laminate body produced at step S23 is molded in anannular shape by making it rounded, thereby producing the statorwinding. Specifically, for example, the stator core 760 and columnarshaped jig having the same diameter as that of the stator core 760 areused such that the laminate body is wounded around the columnar shapedjig, thereby forming the laminate body in the annular shape. Theconductors 800U, 800V and 800W of respective phases constituting thestator winding correspond to a linear portion with reference to FIG. 12.

At step S25, the stator winding produced at step S24 is assembled to thestator core 760 such that the third insulation sheet 740 is positionedbetween the cylindrical shaped stator core 760 made of magneticmaterial, and the U-phase conductor 800U and the first insulation sheet700, thereby producing the stator 770. The stator core 760 isconstituted by, for example, laminating a plurality of electromagneticsteel sheets in the axial direction.

At step S26, the stator 770 is pressed from the rotor side. Thus, asshown in FIG. 79, respective insulation sheets 700, 720 and 740 are madeto be deformed by the pressing to make uniform among a total thicknessdimension at a portion positioned between the W-phase conductor 800W andthe stator core 760 in the first insulation sheet 700, the secondinsulation sheet 720 and the third insulation sheet 740, a totalthickness dimension at a portion positioned between the V-phaseconductor 800V and the stator core 760 in the second insulation sheet720 and the third insulation sheet 740, and a total thickness dimensionat a portion positioned between the U-phase conductor 800U and thestator core 760 in the third insulation sheet 740. Thus, as shown inFIG. 79, a distance in the radial direction from a surface facing therotor to the stator core 760 is made to be a uniform distance LK in therespective U, V, W phase conductors. Note that the stator 770 after theprocess at step S26 is shown in FIG. 79 as a linearly developed view forconvenience reasons.

The stator 770 is pressed from the rotor side, thereby making thethickness dimension of the second insulation sheet 720 at a portion inthe rotor side with respect to the V-phase conductor 800V and a totalthickness dimension of the first and second insulation sheets 700 and720 at a portion in the rotor side with respect to the U-phase conductor800U to be uniform. Thus, the gap is suppressed from being larger.

Note that a termination process is performed for the respectiveconductors 80011, 800V and 800W after the step S26, thereby making thestator winding to be a star-connected wiring. Specifically, end portionsof the conductors adjacently positioned in the circumferential directionare electrically connected via the coil end. Thus, a series connectionbody of a plurality of conductors are formed for each phase. In theabove-described series connection body, first ends are electricallyconnected at the neutral point, and the second end is electricallyconnected to an inverter side. Thus, a stator winding wound by a wavewinding is formed. However, with the stator winding according to thepresent embodiment, m=1 which is different from the stator winding 51shown in FIG. 12.

Subsequently, FIG. 80 illustrate a stator according to a comparativeexample. In FIG. 80, for sake of convenience, the same reference symbolsare applied to configurations corresponding to the above-describedconfigurations.

According to the comparative example, individual insulation sheet 900 iswound around each of the conductors 800U, 800V and 800W corresponding tothe respective phases. In this case, since two layers of the insulationsheet 900 are present between conductors adjacently positioned in thecircumferential direction, a space occupied by the insulation sheet 900becomes larger in the space between conductors adjacently positioned inthe circumferential direction.

In contrast, according to the present embodiment, one layer of theinsulation sheet (first insulation sheet 700) is present between U-phaseconductor 800U and the V-phase conductor 800V in the circumferentialdirection, and also one layer of the insulation sheet (second insulationsheet 720) is present between the V-phase conductor 800V and the W-phaseconductor 800W in the circumferential direction. Thus, interlayerinsulation can be appropriately accomplished while minimizing the spaceoccupied by the insulation sheet in the space between conductorsadjacently positioned in the circumferential direction. As a result, thedimension of the respective conductors 800U, 800V, and 800W in thecircumferential direction can be larger and rated current capable offlowing through the respective conductors 800U, 800V and 800W can beincreased.

According to the present embodiment, only the third insulation sheet 740among the first to third insulation sheets 700, 720 and 740 is presentin the stator core 760 side of the U-phase conductor 800U in the radialdirection. Hence, a cooling ability for the U-phase conductor 800U canbe enhanced in the heat radiation path connected between a portion ofthe U-phase conductor 800U in the stator core 760 side in the radialdirection and the stator core 760.

According to the comparative example shown in FIG. 80, since a portionof the W-phase conductor 800W in the rotor side is covered by theinsulation sheet 900, the cooling ability of the W-phase conductor 800Wis decreased. In contrast, according to the present embodiment, a rotorside portion of the W-phase conductor 800W in the radial direction isexposed. Therefore, a fluid (e.g. air) flowing through the gap betweenthe stator 770 and the rotor enhances the cooing ability of the W-phaseconductor 800W.

For the V-phase conductor 800V between the U, W phase conductors 800Uand the 800W with respect to the radial direction, the first insulationsheet 700 is present in one side thereof in the radial direction and thesecond insulation sheet 720 is present in the other side thereof in theradial direction. Hence, the cooling ability of the V phase conductor800V is considered to be lower than the cooling ability of the U,W-phase conductors. As a result, in the case where the stator winding isenergized, the temperature of the V-phase conductor 800V is consideredto be higher than the temperature of the U, W-phase conductors 800U and800W. In this respect, the V-phase conductor 800V is positioned betweenthe U-phase conductor 800U and the W phase conductor 800W of which thecooling abilities are relatively high, whereby the V-phase conductor800V can be appropriately cooled.

According to the present embodiment, the configuration makes uniformamong a total thickness dimension at a portion positioned between theW-phase conductor 800W and the stator core 760 in the first insulationsheet 700, the second insulation sheet 720 and the third insulationsheet 740, a total thickness dimension at a portion positioned betweenthe V-phase conductor 800V and the stator core 760 in the secondinsulation sheet 720 and the third insulation sheet 740, and a totalthickness dimension at a portion positioned between the U-phaseconductor 800U and the stator core 760 in the third insulation sheet740. Hence, a distance in the radial direction from a surface facing therotor to the stator core 760 is made to be uniform distance LK in therespective U, V, W phase conductors. Thus, a gap between each of the U,V, W-phase conductors 800U, 800V and 800W and the rotor can be uniform,whereby a torque variation of the rotating electric machine can bereduced.

Note that the fifteenth modification can be changed as follows.

For example, in the case where the surface of the U-phase conductor 800Uis coated by the insulating coating, the stator 770 may not include thethird insulation sheet 740.

A temperature sensor such as a thermistor may be provided at only theV-phase conductor 800V among the U-phase, V-phase and W-phase conductorin a state of being contacted. This is because, as described above, thetemperature at V-phase conductor may be the highest among the respectiveconductors 800U, 800V, 800W. In this configuration, the control devicemay lower the torque command to restrict an energization of the statorwinding, when determined that a detection value of the temperaturesensor exceeds the temperature threshold, thereby performing overheatingprotection of the stator 770.

The stator winding may be configured such that two pairs of conductorsconstitutes each winding with a condition of m=2 as shown in FIG. 12. Inthis case, conductors in respective phases shown in FIG. 79 may bearranged such that not one but two conductors are arranged in thecircumferential direction.

The cross-sectional shape of each conductor in respective phases is notlimited to a rectangular, but may be a circular shape, for example.

The configuration of the fifteenth modification can be adapted to astator that constitutes an inner rotor type rotating electric machine.

OTHER EMBODIMENTS

For example, according to the rotating electric machine 500, the inletpassage 571 and the outlet passage 572 of the cooling water passage 545are provided together at the same portion. However, this configurationmay be changed such that the inlet passage 571 and the outlet passage572 are disposed at different portions in the circumferential direction.For example, the inlet passage 571 and the outlet passage 572 aredisposed at 180 degrees different portions in the circumferentialdirection, or at least the inlet passage 571 or the outlet passage 572may be provided in a plural number.

The wheel 400 according to the above-described embodiments is configuredsuch that the rotating shaft 501 protrudes in one side of the rotatingelectric machine 500 in the axial direction. However, this configurationmay be changed such that the rotating shaft 501 protrudes in both sidesof the rotating electric machine in the axial direction. Thus, aconfiguration suitable for a vehicle in which at least one of front andback wheels is configured as one wheel can be accomplished.

As the rotating electric machine 500 used for the wheel 400, an innerrotor type rotating electric machine can be utilized.

The disclosure herein is not limited to the illustrated embodiments. Thedisclosure includes exemplary embodiments and modifications by personsskilled in the art based on the exemplary embodiments. For example, thedisclosure is not limited to the parts and/or element combinationsindicated in the embodiments. The disclosure can be carried out invarious combinations. The disclosure can have additional parts that canbe added to the embodiments. The disclosure includes those in which theparts and/or elements of the embodiments are omitted. The disclosureincludes the replacement or combination of parts and/or elements betweenone embodiment and another. The technical scope disclosed is not limitedto the description of the embodiments. Some technical scopes disclosedare indicated by the statement of the claims and should be understood toinclude all modifications within the meaning and scope equivalent to theclaims.

While the present disclosure has been described in accordance with theexamples, the present disclosure should be understood such that thepresent disclosure is not limited to the examples and structures. Thepresent disclosure also includes various modifications and modificationswithin an equivalent range. Additionally, various combinations andforms, as well as other combinations and forms further including onlyone element, more, or less, also fall within the category and scope ofthe present disclosure.

CONCLUSION

The disclosed aspects herein employ different technical means. Thefeatures and effects disclosed herein are made clearer by reference tothe above-described detailed description and accompanying drawings. Thepresent disclosure provides an armature and a manufacturing methodthereof in which a space occupied by an insulation sheet is minimized ina space between conductors adjacently positioned in the circumferentialdirection.

A first aspect of the present disclosure is an armature adapted to arotating electric machine provided with a field magnet including aplurality of magnetic poles having alternating polarities in acircumferential direction, the armature being disposed facing the fieldmagnet. The armature includes a three-phase armature winding; and anarmature core disposed opposite to the field magnet in a radialdirection with the three-phase armature winding interposed therebetween,in which the armature winding includes conductors arranged in thecircumferential direction at predetermined intervals in the order of afirst phase, a second phase and a third phase; a first insulation sheetis arranged to sequentially pass through a field magnet side withrespect to a first conductor corresponding to the first phase in aradial direction, a portion between the first conductor and a secondconductor corresponding to the second phase, an armature core side withrespect to the second conductor and a third conductor corresponding tothe third phase in the radial direction and a portion between the thirdconductor and the first conductor; and a second insulation sheet isarranged to sequentially pass through a portion opposite to the firstconductor with respect to the first insulation sheet in the radialdirection, a field magnet side with respect to the second conductor inthe radial direction, a portion between the second conductor and thethird conductor, a portion between the third conductor and the firstinsulation sheet in the radial direction and a portion between the thirdconductor and the first insulation sheet in the circumferentialdirection.

According to the first aspect, one layer of the insulation sheet (firstinsulation sheet) is present between the first conductor and the secondconductor in the circumferential direction, and also one layer of theinsulation sheet (second insulation sheet) is present between the secondphase conductor and the third conductor in the circumferentialdirection. Thus, interlayer insulation can be appropriately accomplishedwhile minimizing the space occupied by the insulation sheet in the spacebetween conductors adjacently positioned in the circumferentialdirection.

Further, according to the first aspect, the first and second insulationsheets are not present in the armature core side of the first conductorin the radial direction. Hence, a cooling ability of the first conductorcan be enhanced by a heat radiation path connected between a portion inthe armature core side in the first conductor and the armature core inthe radial direction.

A second aspect is, in the first aspect, the armature is provided with athird insulation sheet interposed between the armature core, and thefirst conductor and the first insulation sheet; a distance in the radialdirection from a circumferential surface in a field magnet side of eachof the first conductor, the second conductor and the third conductor tothe armature core is made to be uniform in a state where a totalthickness dimension at a portion positioned between the third conductorand the armature core in the first insulation sheet, the secondinsulation sheet and the third insulation sheet, a total thicknessdimension at a portion positioned between the second conductor and thearmature core in the second insulation sheet and the third insulationsheet, and a total thickness dimension at a portion positioned betweenthe first conductor and the armature core in the third insulation sheetare uniform.

In the second aspect, in order to enhance the insulation propertiesbetween the first conductor and the armature core, the third insulationsheet is provided to be interposed between the armature core and thefirst conductor and the first insulation sheet.

In this case, the first to third insulation sheets are present betweenthe third conductor and the armature core, the first and secondinsulation sheets are present between the second conductor and thearmature core, and the third insulation sheet is present between thefirst conductor and the armature core. When the total thickness of thefirst to third conductors between the third conductor and the armaturecore, the total thickness of the first and second insulation sheetsbetween the second conductor and the armature core and the totalthickness of the third insulation sheet between the first conductor andthe armature core are different, gaps between respective first to thirdconductors and the field magnet are different.

In this respect, according to the second aspect, the distance in theradial direction from a circumferential surface in a field magnet sideof each of the first conductor, the second conductor and the thirdconductor to the armature core is made to be uniform. Hence, gapsbetween respective first to third conductors and the field magnet can beuniform. As a result, for example, torque variation of the rotatingelectric machine can be reduced.

A third aspect is a manufacturing method of an armature adapted to arotating electric machine provided with a field magnet including aplurality of magnetic poles having alternating polarities in acircumferential direction, in which the armature is disposed facing thefield magnet, and the armature includes a three-phase armature windingand an armature core disposed opposite to the field magnet in a radialdirection with the three-phase armature winding interposed therebetween.The manufacturing method of the armature includes: a process forproducing a first assembly by arranging a first conductor correspondingto a first phase on a first surface of a first insulation sheet withintervals therebetween; a process for producing a second assembly byarranging a third conductor corresponding to a third phase on a firstsurface of a second insulation sheet with intervals therebetween; aprocess for disposing a second conductor corresponding to a second phaseto be adjacent to the first conductor via the first insulation sheet ona second surface of the first insulation sheet that constitutes thefirst assembly; a process for producing a laminate between the firstassembly in which the second conductor is disposed and the secondassembly such that the second conductor is positioned to be adjacent tothe third conductor via the second insulation sheet; a process forproducing the armature winding by making the laminate rounded to bemolded in an annular shape; and a process for producing the armature byassembling the armature winding to the armature core.

According to the third aspect, an armature can be produced in which onelayer of the insulation sheet (first insulation sheet) is presentbetween the first conductor and the second conductor in thecircumferential direction, and also one layer of the insulation sheet(second insulation sheet) is present between the second phase conductorand the third conductor in the circumferential direction.

Further, according to the third aspect, an armature in which the firstand second insulation sheets are not present in the armature core sideof the first conductor in the radial direction can be produced. Hence, acooling ability of the first conductor can be enhanced by a heatradiation path connected between a portion in the armature core side inthe first conductor and the armature core in the radial direction.

A fourth aspect is the manufacturing method in the third aspect providedwith a process in which the armature winding is assembled to thearmature core in a state where the third insulation sheet is interposedbetween the first conductor and the first insulation sheet in theprocess for producing the armature; the armature is pressed from a fieldmagnet side such that a distance in the radial direction from acircumferential surface in a field magnet side of each of the firstconductor, the second conductor and the third conductor to the armaturecore is made to be uniform, thereby making a total thickness dimensionat a portion positioned between the third conductor and the armaturecore in the first insulation sheet, the second insulation sheet and thethird insulation sheet, a total thickness dimension at a portionpositioned between the second conductor and the armature core in thesecond insulation sheet and the third insulation sheet, and a totalthickness dimension at a portion positioned between the first conductorand the armature core in the third insulation sheet to be uniform.

According to the fourth aspect, gaps between respective first to thirdconductors and the field magnet can be uniform. As a result, forexample, torque variation of the rotating electric machine can bereduced.

What is claimed is:
 1. An armature adapted to a rotating electricmachine provided with a field magnet including a plurality of magneticpoles having alternating polarities in a circumferential direction, thearmature being disposed facing the field magnet, the armaturecomprising: a three-phase armature winding; and an armature coredisposed opposite to the field magnet in a radial direction with thethree-phase armature winding interposed therebetween, wherein thearmature winding includes conductors arranged in the circumferentialdirection at predetermined intervals in the order of a first phase, asecond phase and a third phase; a first insulation sheet is arranged tosequentially pass through a field magnet side with respect to a firstconductor corresponding to the first phase in a radial direction, aportion between the first conductor and a second conductor correspondingto the second phase, an armature core side with respect to the secondconductor and a third conductor corresponding to the third phase in theradial direction and a portion between the third conductor and the firstconductor; and a second insulation sheet is arranged to sequentiallypass through a portion opposite to the first conductor with respect tothe first insulation sheet in the radial direction, a field magnet sidewith respect to the second conductor in the radial direction, a portionbetween the second conductor and the third conductor, a portion betweenthe third conductor and the first insulation sheet in the radialdirection and a portion between the third conductor and the firstinsulation sheet in the circumferential direction.
 2. The armatureaccording to claim 1, wherein the armature is provided with a thirdinsulation sheet interposed between the armature core, and the firstconductor and the first insulation sheet; a distance in the radialdirection from a circumferential surface in a field magnet side of eachof the first conductor, the second conductor and the third conductor tothe armature core is made to be uniform in a state where a totalthickness dimension at a portion positioned between the third conductorand the armature core in the first insulation sheet, the secondinsulation sheet and the third insulation sheet, a total thicknessdimension at a portion positioned between the second conductor and thearmature core in the second insulation sheet and the third insulationsheet, and a total thickness dimension at a portion positioned betweenthe first conductor and the armature core in the third insulation sheetare uniform.
 3. A manufacturing method of an armature adapted to arotating electric machine provided with a field magnet including aplurality of magnetic poles having alternating polarities in acircumferential direction, the armature being disposed facing the fieldmagnet, the armature comprising a three-phase armature winding and anarmature core disposed opposite to the field magnet in a radialdirection with the three-phase armature winding interposed therebetween,the manufacturing method of the armature comprising: a process forproducing a first assembly by arranging a first conductor correspondingto a first phase on a first surface of a first insulation sheet withintervals therebetween; a process for producing a second assembly byarranging a third conductor corresponding to a third phase on a firstsurface of a second insulation sheet with intervals therebetween; aprocess for disposing a second conductor corresponding to a second phaseto be adjacent to the first conductor via the first insulation sheet ona second surface of the first insulation sheet that constitutes thefirst assembly; a process for producing a laminate between the firstassembly in which the second conductor is disposed and the secondassembly such that the second conductor is positioned to be adjacent tothe third conductor via the second insulation sheet; a process forproducing the armature winding by making the laminate rounded to bemolded in an annular shape; and a process for producing the armature byassembling the armature winding to the armature core.
 4. Themanufacturing method according to claim 3 includes a process wherein thearmature winding is assembled to the armature core in a state where thethird insulation sheet is interposed between the first conductor and thefirst insulation sheet in the process for producing the armature; thearmature is pressed from a field magnet side such that a distance in theradial direction from a circumferential surface in a field magnet sideof each of the first conductor, the second conductor and the thirdconductor to the armature core is made to be uniform, thereby making atotal thickness dimension at a portion positioned between the thirdconductor and the armature core in the first insulation sheet, thesecond insulation sheet and the third insulation sheet, a totalthickness dimension at a portion positioned between the second conductorand the armature core in the second insulation sheet and the thirdinsulation sheet, and a total thickness dimension at a portionpositioned between the first conductor and the armature core in thethird insulation sheet to be uniform.